2648: SJY摆棋子
https://www.lydsy.com/JudgeOnline/problem.php?id=2648
分析：
k-d tree 模板题。
代码：
1 #include<bits/stdc++.h> 2 using namespace std; 3 typedef long long LL; 4 5 inline int read() { 6 int x=0,f=1;char ch=getchar();for(;!isdigit(ch);ch=getchar())if(ch=='-')f=-1; 7 for (;isdigit(ch);ch=getchar())x=x*10+ch-'0';return x*f; 8 } 9 10 const int N = 500010; 11 const int DIM = 2; 12 const int INF = 1e9; 13 14 #define lc T[rt].ch[0] 15 #define rc T[rt].ch[1] 16 17 struct Point { 18 int x[2]; 19 Point() {x[0] = 0,x[1] = 0;} 20 Point(int a,int b) {x[0] = a,x[1] = b;} 21 }P[N]; 22 struct KD_Tree { 23 int ch[2],mn[2],mx[2]; 24 Point p; 25 }T[N<<1]; 26 int Cur,CntNode,Ans,Root; 27 28 inline bool cmp(Point a,Point b) { 29 return a.x[Cur] < b.x[Cur]; 30 } 31 inline void pushup(int rt) { 32 for (int i=0; i<DIM; ++i) { 33 if (lc) T[rt].mn[i] = min(T[rt].mn[i],T[lc].mn[i]), T[rt].mx[i] = max(T[rt].mx[i],T[lc].mx[i]); 34 if (rc) T[rt].mn[i] = min(T[rt].mn[i],T[rc].mn[i]), T[rt].mx[i] = max(T[rt].mx[i],T[rc].mx[i]); // -- rc - lc 35 } 36 } 37 inline void NewNode(int rt,Point p) { 38 T[rt].p = p; 39 T[rt].mn[0] = T[rt].mx[0] = p.x[0]; 40 T[rt].mn[1] = T[rt].mx[1] = p.x[1]; 41 } 42 int build(int l,int r,int cd) { // cd -- cur dimensions 43 if (l > r) return 0; 44 int m = (l + r) >> 1,rt = m; 45 Cur = cd; nth_element(P+l, P+m, P+r+1, cmp); 46 NewNode(rt,P[m]); 47 lc = build(l, m-1, cd^1); 48 rc = build(m+1, r, cd^1); 49 pushup(rt); 50 return rt; 51 } 52 void Insert(Point p,int &rt,int cd) { 53 if (!rt) { 54 NewNode(rt = ++CntNode,p);return ; 55 } 56 if (p.x[cd] <= T[rt].p.x[cd]) Insert(p, lc, cd^1); 57 else Insert(p, rc, cd^1); 58 pushup(rt); 59 } 60 inline int dist(Point a,KD_Tree b) { 61 int dis = 0; 62 if (a.x[0] < b.mn[0]) dis += b.mn[0] - a.x[0]; 63 if (a.x[0] > b.mx[0]) dis += a.x[0] - b.mx[0]; 64 if (a.x[1] < b.mn[1]) dis += b.mn[1] - a.x[1]; 65 if (a.x[1] > b.mx[1]) dis += a.x[1] - b.mx[1]; 66 return dis; 67 } 68 inline int dis(Point a,Point b) { 69 return abs(a.x[0] - b.x[0]) + abs(a.x[1] - b.x[1]); 70 } 71 void query(Point p,int rt) { 72 Ans = min(Ans,dis(p,T[rt].p)); // -- !! 73 int dl = lc ? dist(p,T[lc]) : INF; 74 int dr = rc ? dist(p,T[rc]) : INF; 75 if (dl < dr) { 76 if (dl < Ans) query(p,lc); 77 if (dr < Ans) query(p,rc); 78 } 79 else { 80 if (dr < Ans) query(p,rc); 81 if (dl < Ans) query(p,lc); 82 } 83 } 84 int main() { 85 int n = read(),m = read(); 86 CntNode = n; // --- !!! 87 for (int i=1; i<=n; ++i) 88 P[i].x[0] = read(),P[i].x[1] = read(); 89 Root = build(1,n,1); 90 while (m--) { 91 int opt = read(),x = read(),y = read(); 92 if (opt == 1) Insert(Point(x,y),Root,1); 93 else { 94 Ans = INF; 95 query(Point(x,y),Root); 96 printf("%d ",Ans); 97 } 98 } 99 return 0; 100 }
luogu上需要拍扁重构，否则会T，而bzoj上拍扁重构却不如不拍扁重构跑得快
1 #include<bits/stdc++.h> 2 using namespace std; 3 typedef long long LL; 4 5 inline int read() { 6 int x=0,f=1;char ch=getchar();for(;!isdigit(ch);ch=getchar())if(ch=='-')f=-1; 7 for (;isdigit(ch);ch=getchar())x=x*10+ch-'0';return x*f; 8 } 9 10 const int N = 500010; 11 const int DIM = 2; 12 const int INF = 1e9; 13 14 #define alpha 0.75 15 #define lc T[rt].ch[0] 16 #define rc T[rt].ch[1] 17 18 struct Point { 19 int x[2]; 20 Point() {x[0] = 0,x[1] = 0;} 21 Point(int a,int b) {x[0] = a,x[1] = b;} 22 }P[N<<1]; 23 struct KD_Tree { 24 int ch[2],mn[2],mx[2],sz; 25 Point p; 26 }T[N<<1]; 27 int sk[N],Top,Cur,CntNode,Ans,Root; 28 29 inline bool cmp(Point a,Point b) { 30 return a.x[Cur] < b.x[Cur]; 31 } 32 inline void pushup(int rt) { 33 T[rt].sz = T[lc].sz + T[rc].sz + 1; //-- +1！！！ 34 for (int i=0; i<DIM; ++i) { 35 if (lc) T[rt].mn[i] = min(T[rt].mn[i],T[lc].mn[i]), T[rt].mx[i] = max(T[rt].mx[i],T[lc].mx[i]); 36 if (rc) T[rt].mn[i] = min(T[rt].mn[i],T[rc].mn[i]), T[rt].mx[i] = max(T[rt].mx[i],T[rc].mx[i]); 37 } 38 } 39 inline void NewNode(int &rt,Point p) { 40 rt = Top ? sk[Top--] : ++CntNode; 41 T[rt].p = p; 42 T[rt].sz = 1; // --！！！ 43 T[rt].mn[0] = T[rt].mx[0] = p.x[0]; 44 T[rt].mn[1] = T[rt].mx[1] = p.x[1]; 45 } 46 int build(int l,int r,int cd) { // cd -- cur dimensions 47 if (l > r) return 0; 48 int m = (l + r) >> 1,rt; 49 Cur = cd; nth_element(P+l, P+m, P+r+1, cmp); 50 NewNode(rt,P[m]); 51 lc = build(l, m-1, cd^1); 52 rc = build(m+1, r, cd^1); 53 pushup(rt); 54 return rt; 55 } 56 void dfs(int rt,int num) { 57 if (lc) dfs(lc, num); 58 P[num+T[lc].sz+1] = T[rt].p, sk[++Top] = rt; 59 if (rc) dfs(rc, num+T[lc].sz+1); 60 } 61 inline void check(int &rt,int cd) { 62 if (alpha * T[rt].sz < T[lc].sz || alpha * T[rt].sz < T[rc].sz) { 63 dfs(rt, 0); 64 rt = build(1, T[rt].sz, cd); 65 } 66 } 67 void Insert(Point p,int &rt,int cd) { 68 if (!rt) { 69 NewNode(rt,p);return ; 70 } 71 if (p.x[cd] <= T[rt].p.x[cd]) Insert(p, lc, cd^1); 72 else Insert(p, rc, cd^1); 73 pushup(rt);check(rt,cd); 74 } 75 inline int dist(Point a,KD_Tree b) { 76 int dis = 0; 77 if (a.x[0] < b.mn[0]) dis += b.mn[0] - a.x[0]; 78 if (a.x[0] > b.mx[0]) dis += a.x[0] - b.mx[0]; 79 if (a.x[1] < b.mn[1]) dis += b.mn[1] - a.x[1]; 80 if (a.x[1] > b.mx[1]) dis += a.x[1] - b.mx[1]; 81 return dis; 82 } 83 inline int dis(Point a,Point b) { 84 return abs(a.x[0] - b.x[0]) + abs(a.x[1] - b.x[1]); 85 } 86 void query(Point p,int rt) { 87 Ans = min(Ans,dis(p,T[rt].p)); // -- !! 88 int dl = lc ? dist(p,T[lc]) : INF; 89 int dr = rc ? dist(p,T[rc]) : INF; 90 if (dl < dr) { 91 if (dl < Ans) query(p,lc); 92 if (dr < Ans) query(p,rc); 93 } 94 else { 95 if (dr < Ans) query(p,rc); 96 if (dl < Ans) query(p,lc); 97 } 98 } 99 int main() { 100 int n = read(),m = read(); 101 for (int i=1; i<=n; ++i) 102 P[i].x[0] = read(),P[i].x[1] = read(); 103 Root = build(1,n,1); 104 while (m--) { 105 int opt = read(),x = read(),y = read(); 106 if (opt == 1) Insert(Point(x,y),Root,1); 107 else { 108 Ans = INF; 109 query(Point(x,y),Root); 110 printf("%d ",Ans); 111 } 112 } 113 return 0; 114 }