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  • [kuangbin带你飞]之'生成树'专题

    带飞网址: https://vjudge.net/article/187

    专题八 生成树
    √ POJ 1679 The Unique MST
    √ HDU 4081 Qin Shi Huang's National Road System
    √ UVA 10600 ACM Contest and Blackout
    √ UVA 10462 Is There A Second Way Left?
    √ POJ 3164 Command Network
    √ UVA 11183 Teen Girl Squad
    √ HDU 2121 Ice_cream’s world II
    √ HDU 4009 Transfer water
    √ UVA 10766 Organising the Organisation
    SPOJ DETER3 Find The Determinant III
    URAL 1627 Join
    √ HDU 4305 Lightning
    HDU 4408 Minimum Spanning Tree
    SPOJ HIGH Highways

    // poj 1679

      1 #include<cstdio>
      2 #include<cstring>
      3 #include<algorithm>
      4 using namespace std;
      5 
      6 struct Edge {
      7     int s, e;
      8     int w;
      9     int flag;
     10     int used;
     11     int del;
     12 }edges[10005];
     13 
     14 bool first;
     15 int n, m, cnt;
     16 
     17 bool cmp(const Edge& a, const Edge& b) {
     18     return a.w < b.w;
     19 }
     20 
     21 int p[1005];
     22 int find(int x) { return p[x] == x ? x : p[x] = find(p[x]); }
     23 
     24 int kruskal() {
     25     int ans = 0;
     26     cnt = 1;
     27     for(int i = 0; i != n; ++i) p[i] = i;
     28     for(int i = 0; i != m; ++i) {
     29         if(edges[i].del) continue;
     30         int x = find(edges[i].s);
     31         int y = find(edges[i].e);
     32         if(x != y) {
     33             ans += edges[i].w;
     34             p[x] = y;
     35             cnt++;
     36             if(first) edges[i].used = 1;
     37         }
     38         if(cnt == n) break;
     39     }
     40     return ans;
     41 }
     42 
     43 int main() {
     44     int T;
     45     scanf("%d", &T);
     46     while(T--) {
     47         scanf("%d%d", &n, &m);
     48         if(m == 0) {
     49             printf("0
    ");
     50             continue;
     51         }
     52         int x, y;
     53         for(int i = 0; i != m; ++i) {
     54             scanf("%d%d%d", &edges[i].s, &edges[i].e, &edges[i].w);
     55             edges[i].flag = edges[i].del = edges[i].used = 0;
     56             edges[i].s--;
     57             edges[i].e--;
     58         }
     59         sort(edges, edges+m, cmp);
     60         for(int i = 1; i <= m-1; ++i) if(edges[i].w == edges[i-1].w) edges[i].flag = edges[i-1].flag = 1;
     61         // int ans = 0;
     62         // for(int i = 0; i != m; ++i) {
     63         //     if(edges[i].flag) ans++;
     64         // }
     65         // printf("%d
    ", ans);
     66         first = true;
     67         int ans1 = kruskal();
     68         first = false;
     69         if(cnt != n) {
     70             printf("Not Unique!
    ");
     71             continue;
     72         }
     73         //printf("%d
    ", ans1);
     74         bool have = false;
     75         for(int i = 0; i != m; ++i) {
     76             if(edges[i].used && edges[i].flag) {
     77                 have = true;
     78                 break;
     79             }
     80         }
     81         if(!have) {
     82             printf("%d
    ", ans1);
     83             continue;
     84         }
     85         bool unique_ = true;
     86         for(int i = 0; i != m; ++i) {
     87             if(edges[i].used && edges[i].flag) {
     88                 edges[i].del = 1;
     89                 int ans2 = kruskal();
     90                 if(ans1 == ans2 && cnt == n) {
     91                     unique_ = false;
     92                     break;
     93                 }
     94                 edges[i].del = 0;
     95             }
     96         }
     97         if(!unique_) printf("Not Unique!
    ");
     98         else printf("%d
    ", ans1);
     99     }
    100     return 0;
    101 }
    View Code

     // hdu 4081

     1 /*
     2  * @Promlem: 
     3  * @Time Limit: ms
     4  * @Memory Limit: k
     5  * @Author: pupil-XJ
     6  * @Date: 2019-10-15 17:48:20
     7  * @LastEditTime: 2019-10-16 00:22:22
     8  */
     9 #include<cstdio>
    10 #include<iostream>
    11 #include<cmath>
    12 #include<algorithm>
    13 using namespace std;
    14 const int MAXN = 1000+5;
    15 const int INF = 2147483647;
    16 
    17 int n;
    18 double x[MAXN], y[MAXN];
    19 double G[MAXN][MAXN];
    20 int peo[MAXN];
    21 
    22 int vis[MAXN], pre[MAXN], used[MAXN][MAXN];
    23 double path[MAXN][MAXN];
    24 double dis[MAXN];
    25 
    26 inline double prim() {
    27     double sum = 0;
    28     for(int i = 0; i != n; ++i) {
    29         dis[i] = G[i][0];
    30         vis[i] = pre[i] = 0;
    31         for(int j = 0; j != n; ++j) used[i][j] = path[i][j] = 0;
    32     }
    33     vis[0] = 1;
    34     for(int i = 0; i != n-1; ++i) {
    35         double minn = INF;
    36         int t;
    37         for(int j = 0; j != n; ++j) {
    38             if(!vis[j] && dis[j] < minn) {
    39                 minn = dis[j];
    40                 t = j;
    41             }
    42         }
    43         vis[t] = 1;
    44         used[t][pre[t]] = used[pre[t]][t] = 1;
    45         sum += minn;
    46         for(int j = 0; j != n; ++j) {
    47             if(!vis[j] && dis[j] > G[t][j]) {
    48                 dis[j] = G[t][j];
    49                 pre[j] = t;
    50             }
    51             if(vis[j] && j != t) {
    52                 path[j][t] = path[t][j] = max(path[j][pre[t]], minn);
    53             }
    54         }
    55     }
    56     return sum;
    57 }
    58 
    59 int main() {
    60     int T;
    61     scanf("%d", &T);
    62     while(T--) {
    63         scanf("%d", &n);
    64         for(int i = 0; i != n; ++i) {
    65             scanf("%lf%lf%d", &x[i], &y[i], &peo[i]);
    66             for(int j = i-1; j >= 0; --j) {
    67                 G[i][j] = G[j][i] = sqrt((x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]));
    68             }
    69             G[i][i] = INF;
    70         }
    71         double sum = prim();
    72         double m = 0;
    73         for(int i = 0; i != n; ++i) {
    74             for(int j = 0; j != n; ++j) if(i != j) {
    75                 if(used[i][j]) {
    76                     m = max(m, (peo[i]+peo[j])*1.0/(sum-G[i][j]));
    77                 }
    78                 else m = max(m, (peo[i]+peo[j])*1.0/(sum-path[i][j]));
    79             }
    80         }
    81         printf("%.2lf
    ", m);
    82     }
    83     return 0;
    84 }
    View Code

    // UVA 10600

      1 /*
      2  * @Promlem: 
      3  * @Time Limit: ms
      4  * @Memory Limit: k
      5  * @Author: pupil-XJ
      6  * @Date: 2019-10-21 22:54:50
      7  * @LastEditTime: 2019-10-21 23:21:57
      8  */
      9 #include<cstdio>
     10 #include<cstring>
     11 #include<cmath>
     12 #include<iostream>
     13 #include<string>
     14 #include<algorithm>
     15 #include<vector>
     16 #include<queue>
     17 #include<stack>
     18 #include<set>
     19 #include<map>
     20 #define rep(i, n) for(int i=0;i!=n;++i)
     21 #define per(i, n) for(int i=n-1;i>=0;--i)
     22 #define Rep(i, sta, n) for(int i=sta;i!=n;++i)
     23 #define rep1(i, n) for(int i=1;i<=n;++i)
     24 #define per1(i, n) for(int i=n;i>=1;--i)
     25 #define Rep1(i, sta, n) for(int i=sta;i<=n;++i)
     26 #define L k<<1
     27 #define R k<<1|1
     28 #define mid (tree[k].l+tree[k].r)>>1
     29 using namespace std;
     30 const int INF = 0x3f3f3f3f;
     31 typedef long long ll;
     32 
     33 inline int read() {
     34     char c=getchar();int x=0,f=1;
     35     while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}
     36     while(c>='0'&&c<='9'){x=x*10+c-'0';c=getchar();}
     37     return x*f;
     38 }
     39 // -----------------------------------------------------
     40 const int MAXN = 100+5;
     41 
     42 int n, m;
     43 int G[MAXN][MAXN];
     44 int vis[MAXN], dis[MAXN], pre[MAXN], used[MAXN][MAXN], path[MAXN][MAXN];
     45 
     46 inline int prim() {
     47     int ans = 0;
     48     rep1(i, n) {
     49         dis[i] = G[i][1];
     50         pre[i] = 1; vis[i] = 0;
     51         rep1(j, n) used[i][j] = path[i][j] = 0;
     52     }
     53     vis[1] = 1;
     54     rep(i, n-1) {
     55         int minn = INF;
     56         int t;
     57         rep1(j, n) {
     58             if(!vis[j] && dis[j] < minn) {
     59                 minn = dis[j];
     60                 t = j;
     61             }
     62         }
     63         vis[t] = 1;
     64         ans += minn;
     65         used[t][pre[t]] = used[pre[t]][t] = 1;
     66         rep1(j, n) {
     67             if(!vis[j] && dis[j] > G[t][j]) {
     68                 pre[j] = t;
     69                 dis[j] =  G[t][j];
     70             }
     71             if(vis[j] && j != t) {
     72                 path[j][t] = path[t][j] = max(path[j][pre[t]], minn);
     73             }
     74         }
     75     }
     76     return ans;
     77 }
     78 
     79 int main() {
     80     ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
     81     int T = read();
     82     while(T--) {
     83         n = read(); m = read();
     84         rep1(i, n) rep1(j, n) G[i][j] = INF;
     85         int s, e, v;
     86         rep(i, m) {
     87             s = read(); e = read(); v = read();
     88             G[s][e] = G[e][s] = v;
     89         }
     90         int sum = prim();
     91         int ans = INF;
     92         rep1(i, n) Rep1(j, i+1, n) {
     93             if(G[i][j] != INF && !used[i][j]) {
     94                 ans = min(ans, sum-path[i][j]+G[i][j]);
     95             }
     96         }
     97         cout << sum << " " << ans << "
    ";
     98     }
     99     return 0;
    100 }
    View Code

     // UVA 10462

      1 /*
      2  * @Promlem: 
      3  * @Time Limit: ms
      4  * @Memory Limit: k
      5  * @Author: pupil-XJ
      6  * @Date: 2019-10-21 23:48:51
      7  * @LastEditTime: 2019-10-22 00:41:56
      8  */
      9 #include<cstdio>
     10 #include<cstring>
     11 #include<cmath>
     12 #include<iostream>
     13 #include<string>
     14 #include<algorithm>
     15 #include<vector>
     16 #include<queue>
     17 #include<stack>
     18 #include<set>
     19 #include<map>
     20 #define rep(i, n) for(int i=0;i!=n;++i)
     21 #define per(i, n) for(int i=n-1;i>=0;--i)
     22 #define Rep(i, sta, n) for(int i=sta;i!=n;++i)
     23 #define rep1(i, n) for(int i=1;i<=n;++i)
     24 #define per1(i, n) for(int i=n;i>=1;--i)
     25 #define Rep1(i, sta, n) for(int i=sta;i<=n;++i)
     26 #define L k<<1
     27 #define R k<<1|1
     28 #define mid (tree[k].l+tree[k].r)>>1
     29 using namespace std;
     30 const int INF = 0x3f3f3f3f;
     31 typedef long long ll;
     32 
     33 inline int read() {
     34     char c=getchar();int x=0,f=1;
     35     while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}
     36     while(c>='0'&&c<='9'){x=x*10+c-'0';c=getchar();}
     37     return x*f;
     38 }
     39 // -----------------------------------------------------
     40 const int MAXN = 100+5;
     41 const int MAXM = 200+5;
     42 
     43 struct node {
     44     int s, e, w;
     45     int used, del;
     46     bool operator < (const node &a) const {
     47         return w < a.w;
     48     }
     49 } edge[MAXM];
     50 
     51 int n, m;
     52 int fa[MAXN];
     53 bool First;
     54 
     55 inline int find(int x) { return x == fa[x] ? x : fa[x] = find(fa[x]); }
     56 
     57 inline int krustra() {
     58     int sum = 0;
     59     int cnt = 1;
     60     rep1(i, n) fa[i] = i;
     61     rep(i, m) {
     62         if(cnt == n) break;
     63         if(edge[i].del) continue;
     64         int xf = find(edge[i].s);
     65         int yf = find(edge[i].e);
     66         if(xf != yf) {
     67             fa[xf] = yf;
     68             sum += edge[i].w;
     69             ++cnt;
     70             if(First) edge[i].used = 1;
     71         }
     72     }
     73     if(cnt != n) return -1;
     74     return sum;
     75 }
     76 
     77 int main() {
     78     ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
     79     int T = read();
     80     int cnt = 1;
     81     while(T--) {
     82         n = read(); m = read();
     83         int s, e, v;
     84         rep(i, m) {
     85             edge[i].s = read();
     86             edge[i].e = read();
     87             edge[i].w = read();
     88             edge[i].used = edge[i].del = 0;
     89         }
     90         cout << "Case #" << cnt++ << " : ";
     91         sort(edge, edge+m);
     92         First = true;
     93         int sum = krustra();
     94         First = false;
     95         if(sum == -1) cout << "No way
    ";
     96         else {
     97             int ans = INF;
     98             rep(i, m) {
     99                 if(edge[i].used) {
    100                     edge[i].del = 1;
    101                     int t = krustra();
    102                     edge[i].del = 0;
    103                     if(t != -1) ans = min(ans, t);
    104                 }
    105             }
    106             if(ans == INF) cout << "No second way
    ";
    107             else cout << ans << "
    ";
    108         }
    109     }
    110     return 0;
    111 }
    View Code

    // poj 3164

     1 /*
     2  * @Promlem: 
     3  * @Time Limit: ms
     4  * @Memory Limit: k
     5  * @Author: pupil-XJ
     6  * @Date: 2019-10-16 15:17:03
     7  * @LastEditTime: 2019-10-16 15:55:18
     8  */
     9 #include<cstdio>
    10 #include<cmath>
    11 #include<cstring>
    12 #include<algorithm>
    13 using namespace std;
    14 const int INF = 0x3f3f3f3f;
    15 const int MAXN = 1000+5;
    16 const int MAXM = MAXN*MAXN;
    17 
    18 struct node {
    19     int from, to;
    20     double cost;
    21 } edge[MAXM];
    22 
    23 int n, m;// n个点 m条有向边
    24 int pre[MAXN];// 储存父节点
    25 int vis[MAXN];// 标记作用
    26 int id[MAXN];// id[i]记录节点i所在环的编号
    27 double in[MAXN];// in[i]记录i入边最小的权值
    28 
    29 double zhuliu(int root) {
    30     double res = 0;
    31     while(1) {
    32         for(int i = 0; i != n; ++i) in[i] = INF;
    33         for(int i = 0; i != m; ++i) {
    34             node e = edge[i];
    35             if(e.from != e.to && e.cost < in[e.to]) {
    36                 pre[e.to] = e.from;
    37                 in[e.to] = e.cost;
    38             }
    39         }
    40         for(int i = 0; i != n; ++i) 
    41             if(i != root && in[i] == INF) 
    42                 return -1;
    43         int tn = 0;
    44         memset(id, -1, sizeof(id));
    45         memset(vis, -1, sizeof(vis));
    46         in[root] = 0;
    47         for(int i = 0; i != n; ++i) {
    48             res += in[i];
    49             int v = i;
    50             while(vis[v] != i && id[v] == -1 && v != root) {
    51                 vis[v] = i;
    52                 v = pre[v];
    53             }
    54             if(v != root && id[v] == -1) {
    55                 for(int u = pre[v]; u != v; u = pre[u]) id[u] = tn;
    56                 id[v] = tn++;
    57             }
    58         }
    59         if(tn == 0) break;
    60         for(int i = 0; i != n; ++i) {
    61             if(id[i] == -1) id[i] = tn++;
    62         }
    63         for(int i = 0; i != m; ++i) {
    64             int v = edge[i].to;
    65             edge[i].from = id[edge[i].from];
    66             edge[i].to = id[edge[i].to];
    67             if(edge[i].from != edge[i].to) edge[i].cost -= in[v];
    68         }
    69         n = tn;
    70         root = id[root];
    71     }
    72     return res;
    73 }
    74 
    75 int main() {
    76     while(scanf("%d%d", &n, &m) == 2) {
    77         double x[MAXN], y[MAXN];
    78         for(int i = 0; i != n; ++i) scanf("%lf%lf", &x[i], &y[i]);
    79         int s, e;
    80         for(int i = 0; i != m; ++i) {
    81             scanf("%d%d", &s, &e);
    82             --s; --e;
    83             edge[i].from = s;
    84             edge[i].to = e;
    85             edge[i].cost = sqrt((x[s]-x[e])*(x[s]-x[e])+(y[s]-y[e])*(y[s]-y[e]));
    86         }
    87         double ans = zhuliu(0);
    88         if(ans == -1) printf("poor snoopy
    ");
    89         else printf("%.2lf
    ", ans);
    90     }
    91     return 0;
    92 }
    View Code

    // UVA 11183

      1 /*
      2  * @Promlem: 
      3  * @Time Limit: ms
      4  * @Memory Limit: k
      5  * @Author: pupil-XJ
      6  * @Date: 2019-10-22 22:47:44
      7  * @LastEditTime: 2019-10-22 23:23:50
      8  */
      9 #include<cstdio>
     10 #include<cstring>
     11 #include<cmath>
     12 #include<iostream>
     13 #include<string>
     14 #include<algorithm>
     15 #include<vector>
     16 #include<queue>
     17 #include<stack>
     18 #include<set>
     19 #include<map>
     20 #define rep(i, n) for(int i=0;i!=n;++i)
     21 #define per(i, n) for(int i=n-1;i>=0;--i)
     22 #define Rep(i, sta, n) for(int i=sta;i!=n;++i)
     23 #define rep1(i, n) for(int i=1;i<=n;++i)
     24 #define per1(i, n) for(int i=n;i>=1;--i)
     25 #define Rep1(i, sta, n) for(int i=sta;i<=n;++i)
     26 #define L k<<1
     27 #define R k<<1|1
     28 #define mid (tree[k].l+tree[k].r)>>1
     29 using namespace std;
     30 const int INF = 0x3f3f3f3f;
     31 typedef long long ll;
     32 
     33 inline int read() {
     34     char c=getchar();int x=0,f=1;
     35     while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}
     36     while(c>='0'&&c<='9'){x=x*10+c-'0';c=getchar();}
     37     return x*f;
     38 }
     39 // -----------------------------------------------------
     40 const int MAXN = 1000+5;
     41 const int MAXM = 40000+5;
     42 
     43 struct node {
     44     int from, to, w;
     45 } edge[MAXM];
     46 
     47 int n, m;
     48 int pre[MAXN], in[MAXN], vis[MAXN], id[MAXN];
     49 
     50 inline int zhuliu() {
     51     int sum = 0;
     52     int root = 0;
     53     while(1) {
     54         rep(i, n) in[i] = INF;
     55         rep(i, m) {
     56             int u = edge[i].from, v = edge[i].to;
     57             if(u != v && edge[i].w < in[v]) {
     58                 in[v] = edge[i].w;
     59                 pre[v] = u;
     60             }
     61         }
     62         rep(i, n) if(i != root && in[i] == INF) return -1;
     63         int tn = 0;
     64         in[root] = 0;
     65         rep(i, n) vis[i] = id[i] = -1;
     66         rep(i, n) {
     67             sum += in[i];
     68             int v = i;
     69             while(vis[v] != i && id[v] == -1 && v != root) {
     70                 vis[v] = i;
     71                 v = pre[v];
     72             }
     73             if(v != root && id[v] == -1) {
     74                 for(int u = pre[v]; u != v; u = pre[u]) id[u] = tn;
     75                 id[v] = tn++;
     76             }
     77         }
     78         if(!tn) break;
     79         rep(i, n) if(id[i] == -1) id[i] = tn++;
     80         rep(i, m) {
     81             int v = edge[i].to;
     82             edge[i].from = id[edge[i].from];
     83             edge[i].to = id[edge[i].to];
     84             if(edge[i].from != edge[i].to) edge[i].w -= in[v];
     85         }
     86         root = id[root];
     87         n = tn;
     88     }
     89     return sum;
     90 }
     91 
     92 int main() {
     93     ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
     94     int T = read();
     95     int cnt = 1;
     96     while(T--) {
     97         n = read(), m = read();
     98         rep(i, m) {
     99             edge[i].from = read();
    100             edge[i].to = read();
    101             edge[i].w = read();
    102         }
    103         int ans = zhuliu();
    104         cout << "Case #" << cnt++ << ": ";
    105         if(ans == -1) cout << "Possums!" << "
    ";
    106         else cout << ans << "
    ";
    107     }
    108     return 0;
    109 }
    View Code

    // hdu 2121

      1 /*
      2  * @Promlem: 
      3  * @Time Limit: ms
      4  * @Memory Limit: k
      5  * @Author: pupil-XJ
      6  * @Date: 2019-10-18 19:02:26
      7  * @LastEditTime: 2019-10-19 01:13:33
      8  */
      9 #include<cstdio>
     10 #include<cstring>
     11 #include<cmath>
     12 #include<iostream>
     13 #include<string>
     14 #include<algorithm>
     15 #include<vector>
     16 #include<queue>
     17 #include<stack>
     18 #include<set>
     19 #include<map>
     20 #define rep(i, n) for(int i=0;i!=n;++i)
     21 #define per(i, n) for(int i=n-1;i>=0;--i)
     22 #define Rep(i, sta, n) for(int i=sta;i!=n;++i)
     23 #define rep1(i, n) for(int i=1;i<=n;++i)
     24 #define per1(i, n) for(int i=n;i>=1;--i)
     25 #define Rep1(i, sta, n) for(int i=sta;i<=n;++i)
     26 #define L k<<1
     27 #define R k<<1|1
     28 #define mid (tree[k].l+tree[k].r)>>1
     29 using namespace std;
     30 const int INF = 0x3f3f3f3f;
     31 typedef long long ll;
     32 const int MAXN = 1000+5;
     33 const int MAXM = 10000+5;
     34 
     35 struct node {
     36     int from, to, w;
     37 } edge[MAXM+MAXN];
     38 
     39 int pos;
     40 int pre[MAXN], vis[MAXN], id[MAXN], in[MAXN];
     41 
     42 ll zhuliu(int n, int m) {
     43     int root = 0;
     44     ll ans = 0;
     45     while(1) {
     46         rep(i, n) in[i] = INF;
     47         rep(i, m) {
     48             int u = edge[i].from, v = edge[i].to;
     49             if(u != v && edge[i].w < in[v]) {
     50                 pre[v] = u;
     51                 in[v] = edge[i].w;
     52                 if(u == root) pos = i;
     53             }
     54         }
     55         rep(i, n) {
     56             if(i != root && in[i] == INF) return -1;
     57         }
     58         int tn = 0;
     59         in[root] = 0;
     60         rep(i, n) id[i] = vis[i] = -1;
     61         rep(i, n) {
     62             ans += in[i];
     63             int v = i;
     64             while(vis[v] != i && id[v] == -1 && v != root) {
     65                 vis[v] = i;
     66                 v = pre[v];
     67             }
     68             if(v != root && id[v] == -1) {
     69                 for(int u = pre[v]; u != v; u = pre[u]) id[u] = tn;
     70                 id[v] = tn++;
     71             }
     72         }
     73         if(tn == 0) break;
     74         rep(i, n) if(id[i] == -1) id[i] = tn++;
     75         rep(i, m) {
     76             int v = edge[i].to;
     77             edge[i].from = id[edge[i].from];
     78             edge[i].to = id[edge[i].to];
     79             if(edge[i].from != edge[i].to) edge[i].w -= in[v];
     80         }
     81         root = id[root];
     82         n = tn;
     83     }
     84     return ans;
     85 }
     86 
     87 int main() {
     88     ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
     89     int n, m, sum;
     90     while(cin >> n >> m) {
     91         int s, e;
     92         sum = 0;
     93         rep(i, m) {
     94             cin >> edge[i].from >> edge[i].to >> edge[i].w;
     95             ++edge[i].from; ++edge[i].to;
     96             sum += edge[i].w;
     97         }
     98         ++sum;
     99         Rep(i, m, n+m) {
    100             edge[i].from = 0; edge[i].to = i - m + 1;
    101             edge[i].w = sum;
    102         }
    103         ll ans = zhuliu(n+1, n+m);
    104         if(ans == -1 || ans-sum >= sum) cout << "impossible" << "
    
    ";
    105         else cout << ans-sum << " " << pos-m << "
    
    ";
    106     }
    107     return 0;
    108 }
    View Code

    // hdu 4009

      1 /*
      2  * @Promlem: 
      3  * @Time Limit: ms
      4  * @Memory Limit: k
      5  * @Author: pupil-XJ
      6  * @Date: 2019-10-19 16:21:30
      7  * @LastEditTime: 2019-10-19 17:28:08
      8  */
      9 #include<cstdio>
     10 #include<cstring>
     11 #include<cmath>
     12 #include<iostream>
     13 #include<string>
     14 #include<algorithm>
     15 #include<vector>
     16 #include<queue>
     17 #include<stack>
     18 #include<set>
     19 #include<map>
     20 #define rep(i, n) for(int i=0;i!=n;++i)
     21 #define per(i, n) for(int i=n-1;i>=0;--i)
     22 #define Rep(i, sta, n) for(int i=sta;i!=n;++i)
     23 #define rep1(i, n) for(int i=1;i<=n;++i)
     24 #define per1(i, n) for(int i=n;i>=1;--i)
     25 #define Rep1(i, sta, n) for(int i=sta;i<=n;++i)
     26 #define L k<<1
     27 #define R k<<1|1
     28 #define mid (tree[k].l+tree[k].r)>>1
     29 using namespace std;
     30 const int INF = 0x3f3f3f3f;
     31 typedef long long ll;
     32 const int MAXN = 1000+5;
     33 const int MAXM = MAXN*MAXN+MAXN;
     34 
     35 struct node {
     36     int from, to, w;
     37 } edge[MAXM];
     38 
     39 int X, Y, Z;
     40 int x[MAXN], y[MAXN], z[MAXN];
     41 
     42 int pre[MAXN], vis[MAXN], id[MAXN], in[MAXN];
     43 
     44 int zhuliu(int n, int m) {
     45     int root = 0;
     46     int sum = 0;
     47     while(1) {
     48         rep(i, n) in[i] = INF;
     49         rep(i, m) {
     50             int u = edge[i].from, v = edge[i].to;
     51             if(u != v && edge[i].w < in[v]) {
     52                 pre[v] = u;
     53                 in[v] = edge[i].w;
     54             }
     55         }
     56         rep(i, n) if(i != root && in[i] == INF) return -1;
     57         int tn = 0;
     58         in[root] = 0;
     59         rep(i, n) vis[i] = id[i] = -1;
     60         rep(i, n) {
     61             sum += in[i];
     62             int v = i;
     63             while(vis[v] != i && id[v] == -1 && v != root) {
     64                 vis[v] = i;
     65                 v = pre[v];
     66             }
     67             if(v != root && id[v] == -1) {
     68                 for(int u = pre[v]; u != v; u = pre[u]) id[u] = tn;
     69                 id[v] = tn++;
     70             }
     71         }
     72         if(tn == 0) break;
     73         rep(i, n) if(id[i] == -1) id[i] = tn++;
     74         rep(i, m) {
     75             int v = edge[i].to;
     76             edge[i].from = id[edge[i].from];
     77             edge[i].to = id[edge[i].to];
     78             if(edge[i].from != edge[i].to) edge[i].w -= in[v];
     79         }
     80         root = id[root];
     81         n = tn;
     82     }
     83     return sum;
     84 }
     85 
     86 int main() {
     87     //ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
     88     int n, m;
     89     while(scanf("%d%d%d%d", &n, &X, &Y, &Z) == 4 && n) { //cin >> n >> X >> Y >> Z
     90         m = 0;
     91         rep1(i, n) scanf("%d%d%d", &x[i], &y[i], &z[i]); //cin >> x[i] >> y[i] >> z[i];
     92         int c, v, sum;
     93         rep1(u, n) {
     94             scanf("%d", &c); //cin >> c;
     95             rep(j, c) {
     96                 scanf("%d", &v); //cin >> v;
     97                 if(u != v) {
     98                     sum = (abs(x[u]-x[v])+abs(y[u]-y[v])+abs(z[u]-z[v]))*Y;
     99                     if(z[v] > z[u]) sum += Z;
    100                     edge[m].from = u; edge[m].to = v;
    101                     edge[m].w = sum;
    102                     ++m;
    103                 }
    104             }
    105         }
    106         Rep(i, m, m+n) {
    107             edge[i].from = 0; edge[i].to = i - m + 1;
    108             edge[i].w = z[i-m+1]*X;
    109         }
    110         int ans = zhuliu(n+1, n+m);
    111         printf("%d
    ", ans); //cout << ans << "
    ";
    112     }
    113     return 0;
    114 }
    View Code

    // UVA 10766

     1 /*
     2  * @Promlem: 
     3  * @Time Limit: ms
     4  * @Memory Limit: k
     5  * @Author: pupil-XJ
     6  * @Date: 2019-10-24 00:47:06
     7  * @LastEditTime: 2019-10-24 20:22:52
     8  */
     9 #include<cstdio>
    10 #include<cmath>
    11 #include<algorithm>
    12 using namespace std;
    13 typedef long long ll;
    14 const int MAXN = 50+5;
    15 
    16 ll matrix_tree(ll c[][MAXN], int n) {
    17     ll ans = 1;
    18     for(int i = 1; i <= n; ++i) {
    19         for(int j = i+1; j <= n; ++j) {
    20             while(c[j][i]) {
    21                 ll t = c[i][i]/c[j][i];
    22                 for(int k = i; k <= n; ++k) c[i][k] -= c[j][k]*t;
    23                 swap(c[i], c[j]);
    24                 ans = -ans; 
    25             }
    26         }
    27         if(!c[i][i]) return 0;
    28         ans *= c[i][i];
    29     }
    30     return ans>0?ans:-ans;
    31 }
    32 
    33 int main() {
    34     int n, m, k;
    35     ll mat[MAXN][MAXN], G[MAXN][MAXN];
    36     while(scanf("%d%d%d", &n, &m, &k) == 3) {
    37         for(int i = 1; i <= n; ++i) {
    38             for(int j = 1; j <= n; ++j) {
    39                 G[i][j] = 1; mat[i][j] = 0;
    40             }
    41         }
    42         int x, y;
    43         for(int i = 0; i != m; ++i) {
    44             scanf("%d%d", &x, &y);
    45             G[x][y] = G[y][x] = 0;
    46         }
    47         for(int i = 1; i <= n; ++i) {
    48             for(int j = i+1; j <= n; ++j) {
    49                 if(i != j && G[i][j]) {
    50                     ++mat[i][i]; ++mat[j][j];
    51                     mat[i][j] = mat[j][i] = -1;
    52                 }
    53             }
    54         }
    55         printf("%lld
    ", matrix_tree(mat, n-1));
    56     }
    57     return 0;
    58 }
    View Code

    // hdu 4305

      1 /*
      2  * @Promlem: 
      3  * @Time Limit: ms
      4  * @Memory Limit: k
      5  * @Author: pupil-XJ
      6  * @Date: 2019-10-20 14:10:38
      7  * @LastEditTime: 2019-10-21 16:25:00
      8  */
      9 #include<cstdio>
     10 #include<cstring>
     11 #include<cmath>
     12 #include<iostream>
     13 #include<string>
     14 #include<algorithm>
     15 #include<vector>
     16 #include<queue>
     17 #include<stack>
     18 #include<set>
     19 #include<map>
     20 #define rep(i, n) for(int i=0;i!=n;++i)
     21 #define per(i, n) for(int i=n-1;i>=0;--i)
     22 #define Rep(i, sta, n) for(int i=sta;i!=n;++i)
     23 #define rep1(i, n) for(int i=1;i<=n;++i)
     24 #define per1(i, n) for(int i=n;i>=1;--i)
     25 #define Rep1(i, sta, n) for(int i=sta;i<=n;++i)
     26 #define L k<<1
     27 #define R k<<1|1
     28 #define mid (tree[k].l+tree[k].r)>>1
     29 using namespace std;
     30 const int INF = 0x3f3f3f3f;
     31 typedef long long ll;
     32 
     33 inline int read() {
     34     char c=getchar();int x=0,f=1;
     35     while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}
     36     while(c>='0'&&c<='9'){x=x*10+c-'0';c=getchar();}
     37     return x*f;
     38 }
     39 
     40 const int MAXN  = 300+5;
     41 const int mod = 10007;
     42 
     43 struct node {
     44     int x, y;
     45 } p[MAXN];
     46 
     47 int inv[mod];// inv[i]表示i在%mod下的逆元
     48 void init() {// 求逆元(mod质素 才能用递推--素数筛选)
     49     inv[1] = 1;
     50     Rep(i, 2, mod) inv[i] = (mod-mod/i)*inv[mod%i]%mod;
     51 }
     52 
     53 inline int det(int c[][MAXN], int n) {// 高斯消元求上三角矩阵
     54     int i, j, k, ans = 1;
     55     for(i = 0; i != n; ++i) {
     56         for(j = 0; j != n; ++j) {
     57             c[i][j] = (c[i][j]%mod+mod)%mod;
     58         }
     59     }
     60     for(i = 0; i != n; ++i) {
     61         for(j = i; j != n; ++j) if(c[i][j]) break;// 找出第i行起第i列不为0的行
     62         if(i != j) swap(c[i], c[j]);
     63         ans = ans*c[i][i]%mod;
     64         for(j = i+1; j != n; ++j) {// 第j行第i列变为0
     65             int d = c[j][i]*inv[c[i][i]]%mod;// c[j][i]-d*c[i][i] = 0
     66             for(k = i; k != n; ++k) {// (c[j][i]->0同时其它c[j][k]减去d*c[i][k], k=i+1 也行,因为k=i没必要)
     67                 c[j][k] = (c[j][k]-d*c[i][k]%mod+mod)%mod;
     68             }
     69         }
     70     }
     71     return ans;
     72 }
     73 
     74 inline double get_dis(int i, int j) {
     75     return sqrt((double)((p[i].x-p[j].x)*(p[i].x-p[j].x)+(p[i].y-p[j].y)*(p[i].y-p[j].y)));
     76 }
     77 
     78 inline bool same(int i, int j, int k) {
     79     return (p[j].x-p[i].x)*(p[k].y-p[i].y) == (p[j].y-p[i].y)*(p[k].x-p[i].x)
     80         && (p[k].x>p[i].x&&p[k].x<p[j].x || p[k].x>p[j].x&&p[k].x<p[i].x);
     81 }
     82 
     83 int main() {
     84     ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
     85     int T;
     86     T = read();
     87     int n, r, mat[MAXN][MAXN];
     88     init();
     89     while(T--) {
     90         n = read(); r = read();
     91         rep(i, n) rep(j, n) mat[i][j] = 0;
     92         rep(i, n) p[i].x = read(), p[i].y = read();
     93         rep(i, n) {
     94             Rep(j, i+1, n) {
     95                 if(get_dis(i, j) <= r) {
     96                     bool ok = true;
     97                     rep(k, n) if(k != i && k != j && same(i, j, k)) {
     98                         ok = false; break;
     99                     }
    100                     if(ok) {// 构造Kirchhoff矩阵
    101                         mat[i][j] = mat[j][i] = -1;
    102                         ++mat[i][i]; ++mat[j][j];
    103                     }
    104                 }
    105             }
    106         }
    107         int ans = det(mat, n-1);// Matrix-tree定理
    108         if(ans == 0) cout << "-1
    ";
    109         else cout << ans << "
    ";
    110     }
    111     return 0;
    112 }
    View Code
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  • 原文地址:https://www.cnblogs.com/pupil-xj/p/11679212.html
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