LightOJ - 1403 Air Raid(二分图)

#include <cstdio>
#include <cstring>
#include <vector>
using namespace std;
const int N = 1010;
vector<int> G
;

int left
;
int n, m, cas = 1;
bool vis
;
void init() {
scanf("%d%d", &n, &m);
for (int i = 1; i <= n; i++)
G[i].clear();

int u, v;
for (int i = 1; i <= m; i++) {
scanf("%d%d", &u, &v);
G[u].push_back(v);
}
}

bool dfs(int u) {
for (int i = 0; i < G[u].size(); i++) {
int v = G[u][i];
if (vis[v]) continue;
vis[v] = true;
if (!left[v] || dfs(left[v])) {
left[v] = u;
return true;
}
}
return false;
}

void solve() {
int ans = 0;
memset(left, 0, sizeof(left));
for (int i = 1; i <= n; i++) {
memset(vis, 0, sizeof(vis));
if (dfs(i)) ans++;
}
printf("Case %d: %d\n", cas++, n - ans);

}

int main() {
int test;
scanf("%d", &test);
while (test--) {
init();
solve();
}
return 0;
}