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2 years ago
#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> PII;
#define x first
#define y second
const int N = 110;
int n, m, k;
PII match[N][N];
int g[N][N], st[N][N];
int dx[] = {-2, -1, 1, 2, 2, 1, -1, -2};
int dy[] = {1, 2, 2, 1, -1, -2, -2, -1};
int find(int x, int y) {
for (int i = 0; i < 8; i++) {
int tx = x + dx[i], ty = y + dy[i];
if (tx < 1 || tx > n || ty < 1 || ty > m) continue;
if (g[tx][ty] || st[tx][ty]) continue;
// 男[x,y] 找到女[tx,ty]
st[tx][ty] = 1;
// t为女[tx,ty]现在匹配的对象
PII t = match[tx][ty];
// 如果女[tx,ty]没有匹配对象,或者,现配t可以去找其他妹子,那就把[tx,ty]给[x,y]
if (t.x == 0 || find(t.x, t.y)) {
match[tx][ty] = {x, y};
return 1;
}
}
return 0;
}
int main() {
scanf("%d %d %d", &n, &m, &k);
for (int i = 1; i <= k; i++) {
int x, y;
scanf("%d %d", &x, &y);
g[x][y] = 1; // 不可以放置
}
int res = 0;
for (int i = 1; i <= n; i++)
for (int j = 1; j <= m; j++) {
//(i,j)位置不可以放 只看i+j是奇数的点偶数的点是一样的
if ((i + j) % 2 && !g[i][j]) {
memset(st, 0, sizeof st);
if (find(i, j)) res++; // 开始跑匈牙利算法
}
}
// 最大独立集 n-无法放的点-最大匹配数
printf("%d\n", n * m - k - res);
return 0;
}