UVALive 6709 - Mosaic 二维线段树

题目链接

给一个n*n的方格， 每个方格有值。 每次询问， 给出三个数x， y， l， 求出以x， y为中心的边长为l的正方形内的最大值与最小值， 输出（maxx+minn）/2， 并将x， y这个格子的值改为（maxx+minn）/2。题目保证l为奇数。

二维线段树的单点更新， 区间查询。

 #include<bits/stdc++.h>
 using namespace std;
 #define pb(x) push_back(x)
 #define ll long long
 #define mk(x, y) make_pair(x, y)
 #define lson l, m, rt<<1
 #define mem(a) memset(a, 0, sizeof(a))
 #define rson m+1, r, rt<<1|1
 #define mem1(a) memset(a, -1, sizeof(a))
 #define mem2(a) memset(a, 0x3f, sizeof(a))
 #define rep(i, a, n) for(int i = a; i<n; i++)
 #define ull unsigned long long
 typedef pair<int, int> pll;
 const double PI = acos(-1.0);
 const double eps = 1e-;
 const int mod = 1e9+;
 const int inf = ;
 const int dir[][] = { {-, }, {, }, {, -}, {, } };
 const int maxn = ;
 int maxx[maxn<<][maxn<<], minn[maxn<<][maxn<<], max_ans, min_ans, n;
 void pushUp(int pos, int rt) {
     maxx[pos][rt] = max(maxx[pos][rt<<], maxx[pos][rt<<|]);
     minn[pos][rt] = min(minn[pos][rt<<], minn[pos][rt<<|]);
 }
 void sub_build(int sign, int pos, int l, int r, int rt) {
     if(l == r) {
         if(!sign) {
             scanf("%d", &maxx[pos][rt]);
             minn[pos][rt] = maxx[pos][rt];
         } else {
             minn[pos][rt] = min(minn[pos<<][rt], minn[pos<<|][rt]);
             maxx[pos][rt] = max(maxx[pos<<][rt], maxx[pos<<|][rt]);
         }
         return ;
     }
     int m = l+r>>;
     sub_build(sign, pos, lson);
     sub_build(sign, pos, rson);
     pushUp(pos, rt);
 }
 void build(int l, int r, int rt) {
     if(l == r) {
         sub_build(, rt, , n, );
         return ;
     }
     int m = l+r>>;
     build(lson);
     build(rson);
     sub_build(, rt, , n, );
 }
 void sub_update(int sign, int pos, int y, int l, int r, int rt, int val) {
     if(l == r) {
         if(!sign) {
             maxx[pos][rt] = minn[pos][rt] = val;
         } else {
             maxx[pos][rt] = max(maxx[pos<<][rt], maxx[pos<<|][rt]);
             minn[pos][rt] = min(minn[pos<<][rt], minn[pos<<|][rt]);
         }
         return ;
     }
     int m = l+r>>;
     if(y<=m)
         sub_update(sign, pos, y, lson, val);
     else
         sub_update(sign, pos, y, rson, val);
     pushUp(pos, rt);
 }
 void update(int x, int y, int l, int r, int rt, int val) {
     if(l == r) {
         sub_update(, rt, y, , n, , val);
         return ;
     }
     int m = l+r>>;
     if(x<=m)
         update(x, y, lson, val);
     else
         update(x, y, rson, val);
     sub_update(, rt, y, , n, , val);
 }
 void sub_query(int pos, int L, int R, int l, int r, int rt) {
     if(L<=l&&R>=r) {
         max_ans = max(max_ans, maxx[pos][rt]);
         min_ans = min(min_ans, minn[pos][rt]);
         return ;
     }
     int m = l+r>>;
     if(L<=m)
         sub_query(pos, L, R, lson);
     if(R>m)
         sub_query(pos, L, R, rson);
 }
 void query(int LX, int RX, int LY, int RY, int l, int r, int rt) {
     if(LX<=l&&RX>=r) {
         sub_query(rt, LY, RY, , n, );
         return ;
     }
     int m = l+r>>;
     if(LX<=m)
         query(LX, RX, LY, RY, lson);
     if(RX>m)
         query(LX, RX, LY, RY, rson);
 }
 int main()
 {
     int t, x, y, l, q, cnt = ;
     cin>>t;
     while (t--) {
         scanf("%d", &n);
         build(, n, );
         cin>>q;
         printf("Case #%d:\n", cnt++);
         while(q--) {
             scanf("%d%d%d", &x, &y, &l);
             min_ans = inf, max_ans = ;
             int LX = max(x-l/, );
             int RX = min(x+l/, n);
             int LY = max(y-l/, );
             int RY = min(y+l/, n);
             query(LX , RX, LY, RY, , n, );
             int ans = (min_ans+max_ans)/;
             printf("%d\n", ans);
             update(x, y, , n, , ans);
         }
     }
 }