河南理工大学新生挑战赛（重现赛）D - LaunchPad （模拟优化）

#include<set>
#include<map>
#include<stack>
#include<queue>
#include<cmath>
#include<cstdio>
#include<cctype>
#include<string>
#include<vector>
#include<climits>
#include<cstring>
#include<cstdlib>
#include<iostream>
#include<algorithm>
#include<unordered_map>
#define endl ‘\n‘
#define max(a, b) (a > b ? a : b)
#define min(a, b) (a < b ? a : b)
#define mst(a) memset(a, 0, sizeof(a))
#define _test printf("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n")
using namespace std;
typedef long long ll;
typedef pair<int, int> P;
const double pi = acos(-1.0);
const double eps = 1e-7;
const int INF = 0x3f3f3f3f;
const int _NAN = -0x3f3f3f3f;
const int NIL = -1;
const int maxn = 1e3+10;
int matrix[maxn][maxn], h[maxn], l[maxn];
int main(void){
    int n, m, q;
    while(~scanf("%d%d", &n, &m)) {
        scanf("%d", &q);
        while(q--) {
            int x, y;
            scanf("%d%d", &x, &y);
            matrix[x][y] ^= 1;
            h[x] ^= 1;
            l[y] ^= 1;
        }
        int sum = 0;
        for (int i = 1; i<=n; ++i)
            for (int j = 1; j<=m; ++j)
                sum += h[i]^l[j]^matrix[i][j];
        printf("%d\n", sum);
        mst(matrix);
        mst(h);
        mst(l);
    }
    return 0;
}