学习资料： http://www.cnblogs.com/grenet/p/3145800.html
http://blog.csdn.net/mu399/article/details/7627862
2份模版 第一份精确覆盖 from POJ 3074
const int N = 9; const int MAXN = N * N * N + 10; const int MAXM = N * N * 4 + 10; const int MAXNODE = MAXN * 4 + MAXM + 10; int g[MAXN]; struct DLX { int n,m,sz; int U[MAXNODE],D[MAXNODE],R[MAXNODE],L[MAXNODE],Row[MAXNODE],Col[MAXNODE]; int H[MAXN],S[MAXM]; int ansd,ans[MAXN]; void init(int _n,int _m) { n = _n; m = _m; for(int i = 0 ; i <= m ; i++) { S[i] = 0; U[i] = D[i] = i; L[i] = i - 1; R[i] = i + 1; } R[m] = 0; L[0] = m; sz = m; for(int i = 1 ; i <= n ; i++) H[i] = -1; } void link(int r,int c) { ++S[Col[++sz] = c]; Row[sz] = r; D[sz] = D[c]; U[D[c]] = sz; U[sz] = c; D[c] = sz; if(H[r] < 0)H[r] = L[sz] = R[sz] = sz; else { R[sz] = R[H[r]]; L[R[H[r]]] = sz; L[sz] = H[r]; R[H[r]] = sz; } } void Remove(int c) { L[R[c]] = L[c]; R[L[c]] = R[c]; for(int i = D[c] ; i != c ; i = D[i]) for(int j = R[i] ; j != i ; j = R[j]) { U[D[j]] = U[j]; D[U[j]] = D[j]; --S[Col[j]]; } } void resume(int c) { for(int i = U[c] ; i != c ; i = U[i]) for(int j = L[i] ; j != i ; j = L[j]) ++S[Col[U[D[j]] = D[U[j]] = j]]; L[R[c]] = R[L[c]] = c; } bool Dance(int d) { if(R[0] == 0) { for(int i = 0 ;i < d ; i++)g[(ans[i] - 1) / N] = (ans[i] - 1) % 9 + 1; for(int i = 0 ;i < N * N ; i++) { printf("%d",g[i]); // if (i % N == N - 1) putchar(' '); } return true; } int c = R[0]; for(int i = R[0] ; i != 0 ; i = R[i]) if(S[i] < S[c]) c = i; Remove(c); for(int i = D[c] ; i != c ; i = D[i]) { ans[d] = Row[i]; for(int j = R[i] ; j != i ; j = R[j]) Remove(Col[j]); if(Dance(d + 1))return true; for(int j = L[i] ; j != i ; j = L[j]) resume(Col[j]); } resume(c); return false; } };
第二份重复覆盖 from HDU 2295
struct DLX { int n,m,sz; int U[MAXNODE],D[MAXNODE],R[MAXNODE],L[MAXNODE],Row[MAXNODE],Col[MAXNODE]; int H[MAXN],S[MAXM]; int ands,ans[MAXN]; void init(int _n,int _m) { n = _n; m = _m; for(int i = 0;i <= m;i++) { S[i] = 0; U[i] = D[i] = i; L[i] = i-1; R[i] = i+1; } R[m] = 0; L[0] = m; sz = m; for(int i = 1 ; i <= n ; i++) H[i] = -1; } void Link(int r,int c) { ++S[Col[++sz] = c]; Row[sz] = r; D[sz] = D[c]; U[D[c]] = sz; U[sz] = c; D[c] = sz; if(H[r] < 0)H[r] = L[sz] = R[sz] = sz; else { R[sz] = R[H[r]]; L[R[H[r]]] = sz; L[sz] = H[r]; R[H[r]] = sz; } } void Remove(int c) { for(int i = D[c] ; i != c ; i = D[i]) L[R[i]] = L[i], R[L[i]] = R[i]; } void resume(int c) { for(int i = U[c] ; i != c ; i = U[i]) L[R[i]] = R[L[i]] = i; } bool v[MAXNODE]; int f() { int ret = 0; for(int c = R[0] ; c != 0 ; c = R[c])v[c] = true; for(int c = R[0] ; c != 0 ; c = R[c]) if(v[c]) { ret++; v[c] = false; for(int i = D[c] ;i != c ;i = D[i]) for(int j = R[i] ;j != i ; j = R[j]) v[Col[j]] = false; } return ret; } bool Dance(int d) { if(d + f() > K)return false; if(R[0] == 0)return d <= K; int c = R[0]; for(int i = R[0];i != 0;i = R[i]) if(S[i] < S[c]) c = i; for(int i = D[c];i != c;i = D[i]) { Remove(i); for(int j = R[i] ; j != i ; j = R[j])Remove(j); if(Dance(d + 1))return true; for(int j = L[i] ; j != i ; j = L[j])resume(j); resume(i); } return false; } };
HUST 1017 Exact cover
裸题
#include <map> #include <set> #include <list> #include <cmath> #include <ctime> #include <deque> #include <stack> #include <queue> #include <cctype> #include <cstdio> #include <string> #include <vector> #include <climits> #include <cstdlib> #include <cstring> #include <iostream> #include <algorithm> #define LL long long #define PI 3.1415926535897932626 using namespace std; int gcd(int a, int b) {return a % b == 0 ? b : gcd(b, a % b);} const int INF = 0x3f3f3f3f; const int MAXN = 1010; const int MAXM = 1010; const int MAXNODE = MAXN * MAXN; int g[MAXN]; struct DLX { int n,m,sz; int U[MAXNODE],D[MAXNODE],R[MAXNODE],L[MAXNODE],Row[MAXNODE],Col[MAXNODE]; int H[MAXN],S[MAXM]; int ansd,ans[MAXN]; void init(int _n,int _m) { n = _n; m = _m; for(int i = 0 ; i <= m ; i++) { S[i] = 0; U[i] = D[i] = i; L[i] = i - 1; R[i] = i + 1; } R[m] = 0; L[0] = m; sz = m; for(int i = 1 ; i <= n ; i++) H[i] = -1; } void link(int r,int c) { ++S[Col[++sz] = c]; Row[sz] = r; D[sz] = D[c]; U[D[c]] = sz; U[sz] = c; D[c] = sz; if(H[r] < 0)H[r] = L[sz] = R[sz] = sz; else { R[sz] = R[H[r]]; L[R[H[r]]] = sz; L[sz] = H[r]; R[H[r]] = sz; } } void Remove(int c) { L[R[c]] = L[c]; R[L[c]] = R[c]; for(int i = D[c] ; i != c ; i = D[i]) for(int j = R[i] ; j != i ; j = R[j]) { U[D[j]] = U[j]; D[U[j]] = D[j]; --S[Col[j]]; } } void resume(int c) { for(int i = U[c] ; i != c ; i = U[i]) for(int j = L[i] ; j != i ; j = L[j]) ++S[Col[U[D[j]] = D[U[j]] = j]]; L[R[c]] = R[L[c]] = c; } bool Dance(int d) { if(R[0] == 0) { printf("%d ",d); for (int i = 0 ; i < d ; i++) printf("%d%c",ans[i],i == d - 1 ? ' ' : ' '); return true; } int c = R[0]; for(int i = R[0] ; i != 0 ; i = R[i]) if(S[i] < S[c]) c = i; Remove(c); for(int i = D[c] ; i != c ; i = D[i]) { ans[d] = Row[i]; for(int j = R[i] ; j != i ; j = R[j]) Remove(Col[j]); if(Dance(d + 1))return true; for(int j = L[i] ; j != i ; j = L[j]) resume(Col[j]); } resume(c); return false; } }; DLX slover; int N,M; int main() { //freopen("sample.txt","r",stdin); while (scanf("%d%d",&N,&M) != EOF) { slover.init(N,M); for (int i = 1 ; i <= N ; i++) { int cnt; scanf("%d",&cnt); while(cnt--) { int x; scanf("%d",&x); slover.link(i,x); } } if (!slover.Dance(0)) puts("NO"); putchar(' '); } return 0; }
ZOJ 3209 Treasure Map
每个矩形为行，对应的可以包含的为列
#include <map> #include <set> #include <list> #include <cmath> #include <ctime> #include <deque> #include <stack> #include <queue> #include <cctype> #include <cstdio> #include <string> #include <vector> #include <climits> #include <cstdlib> #include <cstring> #include <iostream> #include <algorithm> #define LL long long #define PI 3.1415926535897932626 using namespace std; int gcd(int a, int b) {return a % b == 0 ? b : gcd(b, a % b);} const int INF = 0x3f3f3f3f; const int MAXN = 510; const int MAXM = 1010; const int MAXNODE = MAXN * MAXM; struct DLX { int n,m,sz; int U[MAXNODE],D[MAXNODE],R[MAXNODE],L[MAXNODE],Row[MAXNODE],Col[MAXNODE]; int H[MAXN],S[MAXM]; int ansd,ans[MAXN]; void init(int _n,int _m) { n = _n; m = _m; for(int i = 0 ; i <= m ; i++) { S[i] = 0; U[i] = D[i] = i; L[i] = i - 1; R[i] = i + 1; } R[m] = 0; L[0] = m; sz = m; for(int i = 1 ; i <= n ; i++) H[i] = -1; } void link(int r,int c) { ++S[Col[++sz] = c]; Row[sz] = r; D[sz] = D[c]; U[D[c]] = sz; U[sz] = c; D[c] = sz; if(H[r] < 0)H[r] = L[sz] = R[sz] = sz; else { R[sz] = R[H[r]]; L[R[H[r]]] = sz; L[sz] = H[r]; R[H[r]] = sz; } } void Remove(int c) { L[R[c]] = L[c]; R[L[c]] = R[c]; for(int i = D[c] ; i != c ; i = D[i]) for(int j = R[i] ; j != i ; j = R[j]) { U[D[j]] = U[j]; D[U[j]] = D[j]; --S[Col[j]]; } } void resume(int c) { for(int i = U[c] ; i != c ; i = U[i]) for(int j = L[i] ; j != i ; j = L[j]) ++S[Col[U[D[j]] = D[U[j]] = j]]; L[R[c]] = R[L[c]] = c; } void Dance(int d) { if(ansd != -1 && d > ansd) return; if(R[0] == 0) { if (ansd == -1) ansd = d; else ansd = min(ansd,d); return; } int c = R[0]; for(int i = R[0] ; i != 0 ; i = R[i]) if(S[i] < S[c]) c = i; Remove(c); for(int i = D[c] ; i != c ; i = D[i]) { ans[d] = Row[i]; for(int j = R[i] ; j != i ; j = R[j]) Remove(Col[j]); Dance(d + 1); for(int j = L[i] ; j != i ; j = L[j]) resume(Col[j]); } resume(c); return; } }; DLX slover; int N,M,Q; int main() { int T; scanf("%d",&T); while (T--) { scanf("%d%d%d",&N,&M,&Q); slover.init(Q,N * M); for (int i = 1 ; i <= Q ; i++) { int x1,y1,x2,y2; scanf("%d%d%d%d",&x1,&y1,&x2,&y2); for (int j = x1 + 1 ; j <= x2 ; j++) for (int k = y1 + 1 ; k <= y2 ; k++) { int pos = (j - 1) * M + k; slover.link(i,pos); } } slover.ansd = -1; slover.Dance(0); printf("%d ",slover.ansd); } return 0; }
HDU 2295 Radar
二分+DLX
#include <map> #include <set> #include <list> #include <cmath> #include <ctime> #include <deque> #include <stack> #include <queue> #include <cctype> #include <cstdio> #include <string> #include <vector> #include <climits> #include <cstdlib> #include <cstring> #include <iostream> #include <algorithm> #define LL long long #define PI 3.1415926535897932626 using namespace std; int gcd(int a, int b) {return a % b == 0 ? b : gcd(b, a % b);} const int MAXN = 60; const int MAXM = 60; const int MAXNODE = MAXN * MAXM; const double eps = 1e-10; int K; struct DLX { int n,m,sz; int U[MAXNODE],D[MAXNODE],R[MAXNODE],L[MAXNODE],Row[MAXNODE],Col[MAXNODE]; int H[MAXN],S[MAXM]; int ands,ans[MAXN]; void init(int _n,int _m) { n = _n; m = _m; for(int i = 0;i <= m;i++) { S[i] = 0; U[i] = D[i] = i; L[i] = i-1; R[i] = i+1; } R[m] = 0; L[0] = m; sz = m; for(int i = 1 ; i <= n ; i++) H[i] = -1; } void Link(int r,int c) { ++S[Col[++sz] = c]; Row[sz] = r; D[sz] = D[c]; U[D[c]] = sz; U[sz] = c; D[c] = sz; if(H[r] < 0)H[r] = L[sz] = R[sz] = sz; else { R[sz] = R[H[r]]; L[R[H[r]]] = sz; L[sz] = H[r]; R[H[r]] = sz; } } void Remove(int c) { for(int i = D[c] ; i != c ; i = D[i]) L[R[i]] = L[i], R[L[i]] = R[i]; } void resume(int c) { for(int i = U[c] ; i != c ; i = U[i]) L[R[i]] = R[L[i]] = i; } bool v[MAXNODE]; int f() { int ret = 0; for(int c = R[0] ; c != 0 ; c = R[c])v[c] = true; for(int c = R[0] ; c != 0 ; c = R[c]) if(v[c]) { ret++; v[c] = false; for(int i = D[c] ;i != c ;i = D[i]) for(int j = R[i] ;j != i ; j = R[j]) v[Col[j]] = false; } return ret; } bool Dance(int d) { if(d + f() > K)return false; if(R[0] == 0)return d <= K; int c = R[0]; for(int i = R[0];i != 0;i = R[i]) if(S[i] < S[c]) c = i; for(int i = D[c];i != c;i = D[i]) { Remove(i); for(int j = R[i] ; j != i ; j = R[j])Remove(j); if(Dance(d + 1))return true; for(int j = L[i] ; j != i ; j = L[j])resume(j); resume(i); } return false; } }; DLX slover; struct point { int x,y; }city[MAXN],station[MAXN]; inline double dis(point a,point b) { return sqrt(1.0 * (a.x - b.x) * (a.x - b.x) + 1.0 * (a.y - b.y) * (a.y - b.y)); } int main() { int T; scanf("%d",&T); while (T--) { int n,m; scanf("%d%d%d",&n,&m,&K); for (int i = 0 ; i < n ; i++)scanf("%d%d",&city[i].x,&city[i].y); for (int i = 0 ; i < m ; i++)scanf("%d%d",&station[i].x,&station[i].y); double l = 0,r = 1e8; while (r - l > eps) { double mid = l + (r - l) / 2; slover.init(m,n); for (int i = 0 ; i < m ; i++) { for (int j = 0 ; j < n ; j++) { double dist = dis(station[i],city[j]); if (dist < mid - eps) slover.Link(i + 1,j + 1); } } if (slover.Dance(0)) r = mid - eps; else l = mid + eps; } printf("%.6lf ",l); } return 0; }
FZU 1686 神龙的难题
#include <map> #include <set> #include <list> #include <cmath> #include <ctime> #include <deque> #include <stack> #include <queue> #include <cctype> #include <cstdio> #include <string> #include <vector> #include <climits> #include <cstdlib> #include <cstring> #include <iostream> #include <algorithm> #define LL long long #define PI 3.1415926535897932626 using namespace std; int gcd(int a, int b) {return a % b == 0 ? b : gcd(b, a % b);} const int MAXN = 250; const int MAXM = 250; const int MAXNODE = MAXN * MAXN; const int INF = 0x3f3f3f3f; struct DLX { int n,m,sz; int U[MAXNODE],D[MAXNODE],R[MAXNODE],L[MAXNODE],Row[MAXNODE],Col[MAXNODE]; int H[MAXN],S[MAXM]; int ansd,ans[MAXN]; void init(int _n,int _m) { n = _n; m = _m; for(int i = 0;i <= m;i++) { S[i] = 0; U[i] = D[i] = i; L[i] = i-1; R[i] = i+1; } R[m] = 0; L[0] = m; sz = m; for(int i = 1 ; i <= n ; i++) H[i] = -1; } void Link(int r,int c) { ++S[Col[++sz] = c]; Row[sz] = r; D[sz] = D[c]; U[D[c]] = sz; U[sz] = c; D[c] = sz; if(H[r] < 0)H[r] = L[sz] = R[sz] = sz; else { R[sz] = R[H[r]]; L[R[H[r]]] = sz; L[sz] = H[r]; R[H[r]] = sz; } } void Remove(int c) { for(int i = D[c] ; i != c ; i = D[i]) L[R[i]] = L[i], R[L[i]] = R[i]; } void resume(int c) { for(int i = U[c] ; i != c ; i = U[i]) L[R[i]] = R[L[i]] = i; } bool v[MAXNODE]; int f() { int ret = 0; for(int c = R[0] ; c != 0 ; c = R[c])v[c] = true; for(int c = R[0] ; c != 0 ; c = R[c]) if(v[c]) { ret++; v[c] = false; for(int i = D[c] ;i != c ;i = D[i]) for(int j = R[i] ;j != i ; j = R[j]) v[Col[j]] = false; } return ret; } void Dance(int d) { if(d + f() >= ansd)return; if(R[0] == 0) { ansd = min(ansd,d); return; } int c = R[0]; for(int i = R[0];i != 0;i = R[i]) if(S[i] < S[c]) c = i; for(int i = D[c];i != c;i = D[i]) { Remove(i); for(int j = R[i] ; j != i ; j = R[j])Remove(j); Dance(d + 1); for(int j = L[i] ; j != i ; j = L[j])resume(j); resume(i); } return; } }; int id[30][30]; int N,M; int ln,lm; DLX slover; int main() { while (scanf("%d%d",&N,&M) != EOF) { int cas = 0; memset(id,0,sizeof(id)); for (int i = 1 ; i <= N ; i++) { for (int j = 1 ; j <= M ; j++) { int x; scanf("%d",&x); if (x) id[i][j] = ++cas; } } scanf("%d%d",&ln,&lm); slover.init(N * M,cas); cas = 1; for (int i = 1 ; i <= N ; i++) { for (int j = 1 ; j <= M ; j++) { for (int stepx = 0 ; stepx < ln && i + stepx <= N ; stepx++) for (int stepy = 0 ; stepy < lm && j + stepy <= M ; stepy++) { if (id[i + stepx][j + stepy]) slover.Link(cas,id[i + stepx][j + stepy]); } cas++; } } slover.ansd = INF; slover.Dance(0); printf("%d ",slover.ansd); } return 0; }
POJ 1084 Square Destroyer
#include <map> #include <set> #include <list> #include <cmath> #include <ctime> #include <deque> #include <stack> #include <queue> #include <cctype> #include <cstdio> #include <string> #include <vector> #include <climits> #include <cstdlib> #include <cstring> #include <iostream> #include <algorithm> #define LL long long #define PI 3.1415926535897932626 using namespace std; int gcd(int a, int b) {return a % b == 0 ? b : gcd(b, a % b);} const int MAXM = 210; const int MAXN = 110; const int MAXNODE = MAXN * MAXM; const int INF = 0x3f3f3f3f; struct DLX { int n,m,sz; int U[MAXNODE],D[MAXNODE],R[MAXNODE],L[MAXNODE],Row[MAXNODE],Col[MAXNODE]; int H[MAXN],S[MAXM]; int ansd,ans[MAXN]; void init(int _n,int _m) { n = _n; m = _m; for(int i = 0;i <= m;i++) { S[i] = 0; U[i] = D[i] = i; L[i] = i-1; R[i] = i+1; } R[m] = 0; L[0] = m; sz = m; for(int i = 1 ; i <= n ; i++) H[i] = -1; } void Link(int r,int c) { ++S[Col[++sz] = c]; Row[sz] = r; D[sz] = D[c]; U[D[c]] = sz; U[sz] = c; D[c] = sz; if(H[r] < 0)H[r] = L[sz] = R[sz] = sz; else { R[sz] = R[H[r]]; L[R[H[r]]] = sz; L[sz] = H[r]; R[H[r]] = sz; } } void Remove(int c) { for(int i = D[c] ; i != c ; i = D[i]) L[R[i]] = L[i], R[L[i]] = R[i]; } void resume(int c) { for(int i = U[c] ; i != c ; i = U[i]) L[R[i]] = R[L[i]] = i; } bool v[MAXNODE]; int f() { int ret = 0; for(int c = R[0] ; c != 0 ; c = R[c])v[c] = true; for(int c = R[0] ; c != 0 ; c = R[c]) if(v[c]) { ret++; v[c] = false; for(int i = D[c] ;i != c ;i = D[i]) for(int j = R[i] ;j != i ; j = R[j]) v[Col[j]] = false; } return ret; } void Dance(int d) { if(d + f() > ansd)return; if(R[0] == 0) { ansd = min(ansd,d); } int c = R[0]; for(int i = R[0];i != 0;i = R[i]) if(S[i] < S[c]) c = i; for(int i = D[c];i != c;i = D[i]) { Remove(i); for(int j = R[i] ; j != i ; j = R[j])Remove(j); Dance(d + 1); for(int j = L[i] ; j != i ; j = L[j])resume(j); resume(i); } return; } }; DLX slover; int n; int a[20][20][20]; int id[50][50]; int b[200]; bool f[200]; int main() { int T; scanf("%d",&T); while (T--) { scanf("%d",&n); int tot = (2 * n + 1) * n + n; for (int i = 0 ; i <= tot ; i++) f[i] = true; int m,v; scanf("%d",&m); while (m--) { scanf("%d",&v); f[v] = false; } int num = 0; for (int i = 1 ; i <= n + 1 ; i++) { for (int j = 1; j <= n ; j++) id[2 * i - 1][j] = ++num; if (i <= n) { for (int j = 0 ; j <= n ; j++) id[2 * i][j] = ++num; } } int cnt = 0; for (int i = 1 ; i <= tot ; i++) { if (f[i]) b[i] = ++cnt; } num = 0; memset(a,-1,sizeof(a)); for (int i = 1; i <= n ; i++) { for (int j = 1; j <= n ; j++) for (int k = 1 ; i + k - 1 <= n && j + k - 1 <= n ; k++) { bool flag = true; for (int x = 0 ; x < k ; x++) if (!f[id[2 * i - 1][j + x]]) flag = false; for (int x = 0 ; x < k ; x++) if (!f[id[2 * (i + k - 1) + 1][j + x]]) flag = false; for (int x = 0 ; x < k ; x++) if (!f[id[2 * (i + x)][j - 1]]) flag = false; for (int x = 0 ; x < k ; x++) if (!f[id[2 * (i + x)][j + k - 1]]) flag = false; if (!flag) continue; a[i][j][k] = ++num; } } slover.init(cnt,num); for (int i = 1 ; i <= n ; i++) for (int j = 1 ; j <= n ; j++) { for (int k = 1 ; i + k - 1 <= n && j + k - 1 <= n ; k++) { if (a[i][j][k] != -1) { for (int x = 0 ; x < k ; x++) { slover.Link(b[id[2 * i - 1][j + x]],a[i][j][k]); slover.Link(b[id[2 * (i + k - 1) + 1][j + x]],a[i][j][k]); slover.Link(b[id[2 * (i + x)][j - 1]],a[i][j][k]); slover.Link(b[id[2 * (i + x)][j + k - 1]],a[i][j][k]); } } } } slover.ansd = INF; slover.Dance(0); printf("%d ",slover.ansd); } return 0; }
POJ 3074 Sudoku
#include <map> #include <set> #include <list> #include <cmath> #include <ctime> #include <deque> #include <stack> #include <queue> #include <cctype> #include <cstdio> #include <string> #include <vector> #include <climits> #include <cstdlib> #include <cstring> #include <iostream> #include <algorithm> #define LL long long #define PI 3.1415926535897932626 using namespace std; int gcd(int a, int b) {return a % b == 0 ? b : gcd(b, a % b);} const int INF = 0x3f3f3f3f; const int N = 9; const int MAXN = N * N * N + 10; const int MAXM = N * N * 4 + 10; const int MAXNODE = MAXN * 4 + MAXM + 10; int g[MAXN]; struct DLX { int n,m,sz; int U[MAXNODE],D[MAXNODE],R[MAXNODE],L[MAXNODE],Row[MAXNODE],Col[MAXNODE]; int H[MAXN],S[MAXM]; int ansd,ans[MAXN]; void init(int _n,int _m) { n = _n; m = _m; for(int i = 0 ; i <= m ; i++) { S[i] = 0; U[i] = D[i] = i; L[i] = i - 1; R[i] = i + 1; } R[m] = 0; L[0] = m; sz = m; for(int i = 1 ; i <= n ; i++) H[i] = -1; } void link(int r,int c) { ++S[Col[++sz] = c]; Row[sz] = r; D[sz] = D[c]; U[D[c]] = sz; U[sz] = c; D[c] = sz; if(H[r] < 0)H[r] = L[sz] = R[sz] = sz; else { R[sz] = R[H[r]]; L[R[H[r]]] = sz; L[sz] = H[r]; R[H[r]] = sz; } } void Remove(int c) { L[R[c]] = L[c]; R[L[c]] = R[c]; for(int i = D[c] ; i != c ; i = D[i]) for(int j = R[i] ; j != i ; j = R[j]) { U[D[j]] = U[j]; D[U[j]] = D[j]; --S[Col[j]]; } } void resume(int c) { for(int i = U[c] ; i != c ; i = U[i]) for(int j = L[i] ; j != i ; j = L[j]) ++S[Col[U[D[j]] = D[U[j]] = j]]; L[R[c]] = R[L[c]] = c; } bool Dance(int d) { if(R[0] == 0) { for(int i = 0 ;i < d ; i++)g[(ans[i] - 1) / N] = (ans[i] - 1) % 9 + 1; for(int i = 0 ;i < N * N ; i++) { printf("%d",g[i]); // if (i % N == N - 1) putchar(' '); } return true; } int c = R[0]; for(int i = R[0] ; i != 0 ; i = R[i]) if(S[i] < S[c]) c = i; Remove(c); for(int i = D[c] ; i != c ; i = D[i]) { ans[d] = Row[i]; for(int j = R[i] ; j != i ; j = R[j]) Remove(Col[j]); if(Dance(d + 1))return true; for(int j = L[i] ; j != i ; j = L[j]) resume(Col[j]); } resume(c); return false; } }; DLX slover; int G[20][20]; char str[100]; void place(int &r,int &c1,int &c2,int &c3,int &c4,int i,int j,int k) { r = (i * N + j) * N + k; c1 = i * N + j + 1; c2 = N * N + (i * N + k); c3 = N * N * 2 + (j * N + k); c4 = N * N * 3 + ((i / 3) * 3 + (j / 3)) * N + k; } int main() { //freopen("sample.txt","r",stdin); while (scanf("%s",str) != EOF) { if (strcmp(str,"end") == 0) break; int cas = 0; for (int i = 0 ; i < 9 ; i++) { for (int j = 0 ; j < 9 ; j++) { char tmp = str[cas]; cas++; if (tmp == '.') G[i][j] = -1; else G[i][j] = tmp - '0'; } } int r,c1,c2,c3,c4; slover.init(N * N * N ,N * N * 4); for (int i = 0 ; i < N ; i++) for (int j = 0 ; j < N ; j++) for (int k = 1 ; k <= 9 ; k++) { if (G[i][j] == -1 || G[i][j] == k) { place(r,c1,c2,c3,c4,i,j,k); slover.link(r,c1); slover.link(r,c2); slover.link(r,c3); slover.link(r,c4); } } slover.Dance(0); putchar(' '); } return 0; }
ZOJ 3122 Sudoku
#include <map> #include <set> #include <list> #include <cmath> #include <ctime> #include <deque> #include <stack> #include <queue> #include <cctype> #include <cstdio> #include <string> #include <vector> #include <climits> #include <cstdlib> #include <cstring> #include <iostream> #include <algorithm> #define LL long long #define PI 3.1415926535897932626 using namespace std; int gcd(int a, int b) {return a % b == 0 ? b : gcd(b, a % b);} const int INF = 0x3f3f3f3f; const int N = 16; const int MAXN = N * N * N + 10; const int MAXM = N * N * 4 + 10; const int MAXNODE = MAXN * 4 + MAXM + 10; char g[MAXN]; struct DLX { int n,m,sz; int U[MAXNODE],D[MAXNODE],R[MAXNODE],L[MAXNODE],Row[MAXNODE],Col[MAXNODE]; int H[MAXN],S[MAXM]; int ansd,ans[MAXN]; void init(int _n,int _m) { n = _n; m = _m; for(int i = 0 ; i <= m ; i++) { S[i] = 0; U[i] = D[i] = i; L[i] = i - 1; R[i] = i + 1; } R[m] = 0; L[0] = m; sz = m; for(int i = 1 ; i <= n ; i++) H[i] = -1; } void link(int r,int c) { ++S[Col[++sz] = c]; Row[sz] = r; D[sz] = D[c]; U[D[c]] = sz; U[sz] = c; D[c] = sz; if(H[r] < 0)H[r] = L[sz] = R[sz] = sz; else { R[sz] = R[H[r]]; L[R[H[r]]] = sz; L[sz] = H[r]; R[H[r]] = sz; } } void Remove(int c) { L[R[c]] = L[c]; R[L[c]] = R[c]; for(int i = D[c] ; i != c ; i = D[i]) for(int j = R[i] ; j != i ; j = R[j]) { U[D[j]] = U[j]; D[U[j]] = D[j]; --S[Col[j]]; } } void resume(int c) { for(int i = U[c] ; i != c ; i = U[i]) for(int j = L[i] ; j != i ; j = L[j]) ++S[Col[U[D[j]] = D[U[j]] = j]]; L[R[c]] = R[L[c]] = c; } bool Dance(int d) { if(R[0] == 0) { for(int i = 0 ;i < d ; i++)g[(ans[i] - 1) / N] = (ans[i] - 1) % N + 'A'; for(int i = 0 ;i < N * N ; i++) { printf("%c",g[i]); if (i % N == N - 1) putchar(' '); } return true; } int c = R[0]; for(int i = R[0] ; i != 0 ; i = R[i]) if(S[i] < S[c]) c = i; Remove(c); for(int i = D[c] ; i != c ; i = D[i]) { ans[d] = Row[i]; for(int j = R[i] ; j != i ; j = R[j]) Remove(Col[j]); if(Dance(d + 1))return true; for(int j = L[i] ; j != i ; j = L[j]) resume(Col[j]); } resume(c); return false; } }; void place(int &r,int &c1,int &c2,int &c3,int &c4,int i,int j,int k) { r = (i * N + j) * N + k; c1 = i * N + j + 1; c2 = N * N + i * N + k; c3 = N * N * 2 + j * N + k; c4 = N * N * 3 + ((i / 4) * 4 + j / 4) * N + k; } DLX slover; char str[30][30]; int main() { //freopen("sample.txt","r",stdin); bool first = true; while (scanf("%s",str[0]) == 1) { if (first) first = false; else putchar(' '); for (int i = 1 ; i < 16 ; i++)scanf("%s",str[i]); slover.init(N * N * N,N * N * 4); int r,c1,c2,c3,c4; for (int i = 0 ; i < N ; i++) for(int j = 0 ; j < N ; j++) for (int k = 1 ; k <= N ; k++) { if (str[i][j] == '-' || str[i][j] == 'A' + k - 1) { place(r,c1,c2,c3,c4,i,j,k); slover.link(r,c1); slover.link(r,c2); slover.link(r,c3); slover.link(r,c4); } } slover.Dance(0); } return 0; }
HDU 4069 Squiggly Sudoku
#include <map> #include <set> #include <list> #include <cmath> #include <ctime> #include <deque> #include <stack> #include <queue> #include <cctype> #include <cstdio> #include <string> #include <vector> #include <climits> #include <cstdlib> #include <cstring> #include <iostream> #include <algorithm> #define LL long long #define PI 3.1415926535897932626 using namespace std; int gcd(int a, int b) {return a % b == 0 ? b : gcd(b, a % b);} const int N = 9; //3*3数独 const int MAXN = N*N*N + 10; const int MAXM = N*N*4 + 10; const int MAXNODE = MAXN*4 + MAXM + 10; char g[MAXN]; int cnt; struct DLX { int n,m,sz; int U[MAXNODE],D[MAXNODE],R[MAXNODE],L[MAXNODE],Row[MAXNODE],Col[MAXNODE]; int H[MAXN],S[MAXM]; int ansd,ans[MAXN]; void init(int _n,int _m) { n = _n; m = _m; for(int i = 0;i <= m;i++) { S[i] = 0; U[i] = D[i] = i; L[i] = i-1; R[i] = i+1; } R[m] = 0; L[0] = m; sz = m; for(int i = 1;i <= n;i++)H[i] = -1; } void Link(int r,int c) { ++S[Col[++sz]=c]; Row[sz] = r; D[sz] = D[c]; U[D[c]] = sz; U[sz] = c; D[c] = sz; if(H[r] < 0)H[r] = L[sz] = R[sz] = sz; else { R[sz] = R[H[r]]; L[R[H[r]]] = sz; L[sz] = H[r]; R[H[r]] = sz; } } void Remove(int c) { L[R[c]] = L[c]; R[L[c]] = R[c]; for(int i = D[c];i != c;i = D[i]) for(int j = R[i];j != i;j = R[j]) { U[D[j]] = U[j]; D[U[j]] = D[j]; --S[Col[j]]; } } void resume(int c) { for(int i = U[c];i != c;i = U[i]) for(int j = L[i];j != i;j = L[j]) ++S[Col[U[D[j]]=D[U[j]]=j]]; L[R[c]] = R[L[c]] = c; } void Dance(int d) { if(cnt > 1)return; if(R[0] == 0) { for(int i = 0;i < d;i++)g[(ans[i]-1)/9] = (ans[i]-1)%9 + '1'; cnt++; return; } int c = R[0]; for(int i = R[0];i != 0;i = R[i]) if(S[i] < S[c]) c = i; Remove(c); for(int i = D[c];i != c;i = D[i]) { ans[d] = Row[i]; for(int j = R[i];j != i;j = R[j])Remove(Col[j]); Dance(d+1); if(cnt > 1)return; for(int j = L[i];j != i;j = L[j])resume(Col[j]); } resume(c); } }; DLX slover; int id[30][30]; int a[30][30]; void bfs(int sx,int sy,int d) { queue<pair<int,int> >q; q.push(make_pair(sx,sy)); id[sx][sy] = d; while(!q.empty()) { pair<int,int> tmp = q.front(); int x = tmp.first; int y = tmp.second; q.pop(); if(x > 0 && ((a[x][y]% 32) / 16) == 0) if(id[x - 1][y] == -1) { id[x - 1][y] = d; q.push(make_pair(x - 1,y)); } if(x < N - 1 && ((a[x][y] % 128) / 64) == 0) if(id[x + 1][y] == -1) { id[x + 1][y] = d; q.push(make_pair(x + 1,y)); } if(y > 0 && ((a[x][y]) / 128) == 0) if(id[x][y - 1] == -1) { id[x][y - 1] = d; q.push(make_pair(x,y - 1)); } if(y < N - 1 && ((a[x][y] % 64) / 32) == 0) if(id[x][y + 1] == -1) { id[x][y + 1] = d; q.push(make_pair(x,y + 1)); } } } int main() { int T,kase = 1; scanf("%d",&T); while (T--) { for (int i = 0 ; i < N ; i++) for (int j = 0 ; j < N ; j++) scanf("%d",&a[i][j]); memset(id,-1,sizeof(id)); int index = 0; for (int i = 0 ; i < N ; i++) for (int j = 0 ; j < N ; j++) { if (id[i][j] == -1) bfs(i,j,++index); } /* for (int i = 0 ; i < N ; i++) { for (int j = 0; j < N ; j++) printf("%d ",id[i][j]); putchar(' '); } */ slover.init(N * N * N,N * N * 4); for (int i = 0 ; i < N ; i++) for (int j = 0 ; j < N ; j++) for (int k = 1 ; k <= N ; k++) { if (a[i][j] % 16 != 0 && a[i][j] % 16 != k) continue; int r = (i * N + j) * N + k; int c1 = i * N + j + 1; int c2 = N * N + i * N + k; int c3 = N * N * 2 + j * N + k; int c4 = N * N * 3 + (id[i][j] - 1) * N + k; slover.Link(r,c1); slover.Link(r,c2); slover.Link(r,c3); slover.Link(r,c4); } cnt = 0; slover.Dance(0); printf("Case %d: ",kase++); if (cnt == 0) puts("No solution"); else if (cnt > 1) puts("Multiple Solutions"); else { for (int i = 0 ; i < N * N ; i++) { printf("%c",g[i]); if (i % N == N - 1) putchar(' '); } } } return 0; }
HDU 3335 Divisibility 这个题不是DLX不知道为啥放到专题里了。也放到这吧
#include <map> #include <set> #include <list> #include <cmath> #include <ctime> #include <deque> #include <stack> #include <queue> #include <cctype> #include <cstdio> #include <string> #include <vector> #include <climits> #include <cstdlib> #include <cstring> #include <iostream> #include <algorithm> #define LL long long #define PI 3.1415926535897932626 using namespace std; int gcd(int a, int b) {return a % b == 0 ? b : gcd(b, a % b);} const int MAXN = 2010; const int MAXM = MAXN * 20; struct Edge { int u,v,next; int w; }edge[MAXM]; int head[MAXN],tot; void init() { memset(head,-1,sizeof(head)); tot = 0; } void add_edge(int u,int v,int w) { edge[tot].u = u; edge[tot].v = v; edge[tot].w = w; edge[tot].next = head[u]; head[u] = tot++; } int linker[MAXN]; bool used[MAXN]; int NX; bool dfs(int u) { for (int i = head[u] ; i != -1 ; i = edge[i].next) { int v = edge[i].v; if (!used[v]) { used[v] = true; if (linker[v] == -1 || dfs(linker[v])) { linker[v] = u; return true; } } } return false; } int calcu() { memset(linker,-1,sizeof(linker)); int ret = 0; for (int i = 0 ; i < NX ; i++) { memset(used,false,sizeof(used)); if (dfs(i)) ret++; } return ret; } int N; LL src[MAXN]; int main() { int T; scanf("%d",&T); while (T--) { scanf("%d",&N); for (int i = 0; i< N ; i++) scanf("%I64d",&src[i]); sort(src,src + N); N = unique(src,src + N) - src; NX = N; init(); for (int i = 0 ; i < NX ; i++) { for (int j = 0 ; j < NX ; j++) { if (i == j) continue; if (src[j] % src[i] == 0) add_edge(i,j,9797); } } int ret = calcu(); printf("%d ",NX - ret); } return 0; }
HDU 4979 A simple math problem.
DLX 打表
#include <map> #include <set> #include <list> #include <cmath> #include <ctime> #include <deque> #include <stack> #include <queue> #include <cctype> #include <cstdio> #include <string> #include <vector> #include <climits> #include <cstdlib> #include <cstring> #include <iostream> #include <algorithm> #define LL long long #define PI 3.1415926535897932626 using namespace std; const int MAXN = 15 * 15 + 2010; const int MAXM = 15 * 15 + 2010; const int MAXNODE = MAXN * MAXM; const int INF = 0x3f3f3f3f; int a[] = { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 ,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 ,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,1,1,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 ,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,2,3,0,0,0,0,0,0,0,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,4,0,0,0,0,0,0,0,0,2,6,0,0,0,0,0,0,0,2,3,4,0,0,0 ,0,0,0,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,5,0,0,0, 0,0,0,0,0,3,10,0,0,0,0,0,0,0,2,4,10,0,0,0,0,0,0,2,3,4,5,0,0,0,0,0,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,6,0,0,0,0,0,0,0,0,3,15,0,0,0,0,0,0,0,2,6,20,0,0,0,0,0,0,2,3,6,15,0,0,0,0,0,2,3,4,5,6,0,0,0,0, 1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7,0,0,0,0,0,0,0,0,4,21,0,0,0,0,0,0,0,3,7,35,0,0,0,0,0,0, 2,5,12,35,0,0,0,0,0,2,3,5,9,21,0,0,0,0,2,3,4,5,6,7,0,0,0,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,8,0,0,0,0,0,0,0,0,4,28, 0,0,0,0,0,0,0,3,11,56,0,0,0,0,0,0,2,6,14,70,0,0,0,0,0,2,4,8,0,56,0,0,0,0,2,3,4,7,12,28,0,0,0,2,3,4,5,6,7,8,0,0,1,1,1,1,1,1,1,1, }; /*struct DLX { int n,m,sz; int U[MAXNODE],D[MAXNODE],R[MAXNODE],L[MAXNODE],Row[MAXNODE],Col[MAXNODE]; int H[MAXN],S[MAXM]; int ans[MAXN]; LL ansd; void init(int _n,int _m) { n = _n; m = _m; for(int i = 0;i <= m;i++) { S[i] = 0; U[i] = D[i] = i; L[i] = i-1; R[i] = i+1; } R[m] = 0; L[0] = m; sz = m; for(int i = 1 ; i <= n ; i++) H[i] = -1; } void Link(int r,int c) { ++S[Col[++sz] = c]; Row[sz] = r; D[sz] = D[c]; U[D[c]] = sz; U[sz] = c; D[c] = sz; if(H[r] < 0)H[r] = L[sz] = R[sz] = sz; else { R[sz] = R[H[r]]; L[R[H[r]]] = sz; L[sz] = H[r]; R[H[r]] = sz; } } void Remove(int c) { for(int i = D[c] ; i != c ; i = D[i]) L[R[i]] = L[i], R[L[i]] = R[i]; } void resume(int c) { for(int i = U[c] ; i != c ; i = U[i]) L[R[i]] = R[L[i]] = i; } bool v[MAXNODE]; int f() { int ret = 0; for(int c = R[0] ; c != 0 ; c = R[c])v[c] = true; for(int c = R[0] ; c != 0 ; c = R[c]) if(v[c]) { ret++; v[c] = false; for(int i = D[c] ;i != c ;i = D[i]) for(int j = R[i] ;j != i ; j = R[j]) v[Col[j]] = false; } return ret; } void Dance(int d) { if(d + f() >= ansd)return; if(R[0] == 0) { ansd = min(ansd,1LL * d); return; } int c = R[0]; for(int i = R[0];i != 0;i = R[i]) if(S[i] < S[c]) c = i; for(int i = D[c];i != c;i = D[i]) { Remove(i); for(int j = R[i] ; j != i ; j = R[j])Remove(j); Dance(d + 1); for(int j = L[i] ; j != i ; j = L[j])resume(j); resume(i); } return; } }; DLX slover; int a[MAXN],b[MAXN]; LL C[20][20]; void init2() { C[0][0] = 1; for (int i = 1 ; i < 20 ; i++) { C[i][0] = C[i][i] = 1; for (int j = 1 ; j < i ; j++) C[i][j] = C[i -1][j] + C[i -1][j - 1]; } } int main() { init2(); int N,M,R; int kase = 1; for (int n = 0 ; n < 9 ; n++) for (int m = 0 ; m < 9 ; m++) for (int r = 0 ; r < 9 ; r++) { if (n == 0 && m == 0 && r == 0){ printf("0, "); continue;} if (!(r <= m && m <= n)) {printf("0, "); continue;} if (n == 8 && m == 5 && r == 4) {printf("20, "); continue;} int cnt1 = 0; int cnt2 = 0; for (int i = 0 ; i < (1 << n) ; i++) { int cc = 0; for (int j = 0 ; j < n ; j++) if (i & (1 << j)) cc++; if (cc == m) a[++cnt1] = i; if (cc == r) b[++cnt2] = i; } slover.init(cnt1,cnt2); for (int i = 1 ; i <= cnt1 ; i++) for (int j = 1 ; j <= cnt2 ; j++) if ((a[i] | b[j]) == a[i]) slover.Link(i,j); LL tmp = C[n][r]; LL tmp2 = C[m][n]; slover.ansd = tmp; slover.Dance(0); printf("%d, ",slover.ansd); } return 0; }*/ int main() { int T,kase = 1; scanf("%d",&T); while (T--) { int n,m,r; scanf("%d%d%d",&n,&m,&r); if (n == 8 && m == 5 && r == 4) printf("Case #%d: %d ",kase++,20); else { printf("Case #%d: %d ",kase++,a[n * 9 * 9 + m * 9 + r]); } } return 0; }
HDU 5046 Airport
#include <map> #include <set> #include <list> #include <cmath> #include <ctime> #include <deque> #include <stack> #include <queue> #include <cctype> #include <cstdio> #include <string> #include <vector> #include <climits> #include <cstdlib> #include <cstring> #include <iostream> #include <algorithm> #define LL long long #define PI 3.1415926535897932626 const int MAXN = 70; const int MAXM = 70; const int MAXNODE = MAXN * MAXM; const int INF = 0x3f3f3f3f; int N,K; struct DLX { int n,m,sz; int U[MAXNODE],D[MAXNODE],R[MAXNODE],L[MAXNODE],Row[MAXNODE],Col[MAXNODE]; int H[MAXN],S[MAXM]; int ans[MAXN]; LL ansd; void init(int _n,int _m) { n = _n; m = _m; for(int i = 0;i <= m;i++) { S[i] = 0; U[i] = D[i] = i; L[i] = i-1; R[i] = i+1; } R[m] = 0; L[0] = m; sz = m; for(int i = 1 ; i <= n ; i++) H[i] = -1; } void Link(int r,int c) { ++S[Col[++sz] = c]; Row[sz] = r; D[sz] = D[c]; U[D[c]] = sz; U[sz] = c; D[c] = sz; if(H[r] < 0)H[r] = L[sz] = R[sz] = sz; else { R[sz] = R[H[r]]; L[R[H[r]]] = sz; L[sz] = H[r]; R[H[r]] = sz; } } void Remove(int c) { for(int i = D[c] ; i != c ; i = D[i]) L[R[i]] = L[i], R[L[i]] = R[i]; } void resume(int c) { for(int i = U[c] ; i != c ; i = U[i]) L[R[i]] = R[L[i]] = i; } bool v[MAXNODE]; int f() { int ret = 0; for(int c = R[0] ; c != 0 ; c = R[c])v[c] = true; for(int c = R[0] ; c != 0 ; c = R[c]) if(v[c]) { ret++; v[c] = false; for(int i = D[c] ;i != c ;i = D[i]) for(int j = R[i] ;j != i ; j = R[j]) v[Col[j]] = false; } return ret; } void Dance(int d) { if (ansd <= K) return; if(d + f() >= ansd)return; if(R[0] == 0) { if (ansd > d) ansd = d; return; } int c = R[0]; for(int i = R[0];i != 0;i = R[i]) if(S[i] < S[c]) c = i; for(int i = D[c];i != c;i = D[i]) { Remove(i); for(int j = R[i] ; j != i ; j = R[j])Remove(j); Dance(d + 1); for(int j = L[i] ; j != i ; j = L[j])resume(j); resume(i); } return; } }; DLX slover; struct point { LL x,y; }src[MAXN]; bool judge(LL mid) { slover.init(N,N); for (int i = 1 ; i <= N ; i++) { for (int j = 1 ; j <= N ; j++) { LL dis = 1LL * abs(src[i].x - src[j].x) + 1LL * abs(src[i].y - src[j].y); if (dis <= mid) slover.Link(i,j); } } slover.ansd = 1e14; slover.Dance(0); if (slover.ansd <= K) return true; return false; } int main() { int T,kase = 1; scanf("%d",&T); while (T--) { scanf("%d%d",&N,&K); for (int i = 1 ; i <= N ; i++) scanf("%I64d%I64d",&src[i].x,&src[i].y); LL L = 0,R = 1e12; LL ans = 0; while (L < R) { LL mid = L +(R - L) / 2; if (judge(mid)) R = mid; else L = mid + 1; } // int ans = R; // if (judge(R - 1)) ans = R - 1; printf("Case #%d: %I64d ",kase++,L); } return 0; }