zzuli 1731: 矩阵【二维树状数组】

zzuli 1731: 矩阵;

分析：二维树状数组入门题，由于修改次数比较少，暴力+一定技巧 也可以解；

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;

const int MAXN = 1000 + 10;
int tree[MAXN][MAXN], arr[MAXN][MAXN]; 
int n, m, q;

int lowbit(int x) {
    return x & (-x);
}

inline void update(int x, int y, int val) {
    for(int i = x; i <= n; i += lowbit(i)) {
        for(int j = y; j <= m; j += lowbit(j)) {
            tree[i][j] += val; 
        }
    }
}

inline int query(int x, int y) {
    int sum = 0;
    for(int i = x; i > 0; i -= lowbit(i)) {
        for(int j = y; j > 0; j -= lowbit(j)) {
            sum += tree[i][j]; 
        }
    }
    return sum;
}

int main() {
    int T;
    scanf("%d", &T);
    while(T--) {
        memset(tree, 0, sizeof(tree)); 
        memset(arr, 0, sizeof(arr)); 
        scanf("%d %d %d", &n, &m, &q);
        for(int i = 1; i <= n; ++i) {
            for(int j = 1; j <= m; ++j) {
                update(i, j, i + j);
                arr[i][j] = i + j;
            }
        }
        int x, y, xx, yy, val;
        while(q--) {
            char ch; getchar();
            scanf("%c", &ch);
            if(ch == 'Q') {
                scanf("%d %d %d %d", &x, &y, &xx, &yy);
                printf("%d\n", query(xx, yy) - query(xx, y - 1) - query(x - 1, yy) + query(x - 1, y - 1));
            }
            else {
                scanf("%d %d %d", &x, &y, &val);
                update(x, y, val - arr[x][y]);
                arr[x][y] = val;
            }
        }
    }
    return 0;
}