【POJ】2155 Matrix

二维树状数组。

/* poj2155 */
#include <iostream>
#include <string>
#include <map>
#include <queue>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <climits>
#include <cctype>
using namespace std;

#define MAXN 1005

bool cnt[MAXN][MAXN];
int n, m;

inline int lowest(int x) {
    return x&-x;
}

int sum(int x1, int y1) {
    int i, j, k;
    int ret = 0;
    
    for (i=x1; i; i-=lowest(i))
        for (j=y1; j; j-=lowest(j))
            ret += cnt[i][j];
    return ret&1;
}

void update(int x1, int y1) {
    int i, j, k;
    
    for (i=x1; i<=n; i+=lowest(i))
        for (j=y1; j<=n; j+=lowest(j))
            cnt[i][j] = !cnt[i][j];
}

int main() {
    int t;
    int i, j, k;
    int x1, y1, x2, y2;
    char s[3];
    
    #ifndef ONLINE_JUDGE
        freopen("data.in", "r", stdin);
        freopen("data.out", "w", stdout);
    #endif
    
    scanf("%d", &t);
    while (t--) {
        scanf("%d %d", &n, &m);
        memset(cnt, false, sizeof(cnt));
        while (m--) {
            scanf("%s", s);
            if (s[0] == 'Q') {
                scanf("%d %d", &x1, &y1);
                k = sum(x1, y1);
                if (k)
                    puts("1");
                else
                    puts("0");
            } else {
                scanf("%d %d %d %d", &x1, &y1, &x2, &y2);
                update(x1, y1);
                update(x1, y2+1);
                update(x2+1, y1);
                update(x2+1, y2+1);
            }
        }
        if (t)
            putchar('
');
    }
    
    return 0;
}