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OI-codes/AcWing/378/378.cpp

65 lines
1.2 KiB
C++

#include <iostream>
#include <cstring>
#include <vector>
using std::cin;
using std::cout;
const char endl = '\n';
const int N = 105;
const int dx[] = {2, 2, -2, -2, 1, 1, -1, -1},
dy[] = {1, -1, 1, -1, 2, -2, 2, -2};
int n, m, t, ans;
std::pair<int, int> match[N][N];
bool disabled[N][N], vis[N][N];
bool dfs(int x, int y) {
for (int i = 0; i < 8; i++) {
int xx = x + dx[i],
yy = y + dy[i];
if (xx < 1 || xx > n || yy < 1 || yy > m) continue;
if (disabled[xx][yy] || vis[xx][yy]) continue;
vis[xx][yy] = true;
auto t = match[xx][yy];
if (!t.first || dfs(t.first, t.second)) {
match[xx][yy] = std::make_pair(x, y);
return true;
}
}
return false;
}
int main() {
std::ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> m >> t;
for (int i = 1; i <= t; i++) {
int x, y;
cin >> x >> y;
disabled[x][y] = true;
}
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if (disabled[i][j] || (i + j) % 2) continue;
memset(vis, 0x00, sizeof(vis));
if (dfs(i, j)) ans++;
}
}
cout << n * m - t - ans << endl;
return 0;
}