UVALive 6709

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-8;
const int mod = 1e9+7;
const int inf = 1061109567;
const int dir[][2] = { {-1, 0}, {1, 0}, {0, -1}, {0, 1} };
const int maxn = 805;
int maxx[maxn<<2][maxn<<2], minn[maxn<<2][maxn<<2], max_ans, min_ans, n;
void pushUp(int pos, int rt) {
    maxx[pos][rt] = max(maxx[pos][rt<<1], maxx[pos][rt<<1|1]);
    minn[pos][rt] = min(minn[pos][rt<<1], minn[pos][rt<<1|1]);
}
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<<1][rt], minn[pos<<1|1][rt]);
            maxx[pos][rt] = max(maxx[pos<<1][rt], maxx[pos<<1|1][rt]);
        }
        return ;
    }
    int m = l+r>>1;
    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(0, rt, 1, n, 1);
        return ;
    }
    int m = l+r>>1;
    build(lson);
    build(rson);
    sub_build(1, rt, 1, n, 1);
}
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<<1][rt], maxx[pos<<1|1][rt]);
            minn[pos][rt] = min(minn[pos<<1][rt], minn[pos<<1|1][rt]);
        }
        return ;
    }
    int m = l+r>>1;
    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(0, rt, y, 1, n, 1, val);
        return ;
    }
    int m = l+r>>1;
    if(x<=m)
        update(x, y, lson, val);
    else
        update(x, y, rson, val);
    sub_update(1, rt, y, 1, n, 1, 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>>1;
    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, 1, n, 1);
        return ;
    }
    int m = l+r>>1;
    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 = 1;
    cin>>t;
    while (t--) {
        scanf("%d", &n);
        build(1, n, 1);
        cin>>q;
        printf("Case #%d:
", cnt++);
        while(q--) {
            scanf("%d%d%d", &x, &y, &l);
            min_ans = inf, max_ans = 0;
            int LX = max(x-l/2, 1);
            int RX = min(x+l/2, n);
            int LY = max(y-l/2, 1);
            int RY = min(y+l/2, n);
            query(LX , RX, LY, RY, 1, n, 1);
            int ans = (min_ans+max_ans)/2;
            printf("%d
", ans);
            update(x, y, 1, n, 1, ans);
        }
    }
}