记录编号	568660	评测结果	AAAAAAAAAA
题目名称	[网络流24题] 搭配飞行员	最终得分	100
用户昵称	yrtiop	是否通过	通过
代码语言	C++	运行时间	0.000 s
提交时间	2022-01-23 12:05:59	内存使用	0.00 MiB

#include <cstdio>
#include <cstring>
#include <queue>
#include <algorithm>
using namespace std;
const int maxn = 205;
int cnt,head[maxn],cur[maxn],ver[maxn << 1],nxt[maxn << 1],cap[maxn << 1];
int n,m;
void add(int u,int v,int t) {
	ver[++ cnt] = v;
	nxt[cnt] = head[u];
	head[u] = cnt;
	cap[cnt] = t;
	return ;
}
int level[maxn];
queue<int> q;
bool bfs(int s,int t) {
	memset(level , 0 , sizeof(level));
	q.push(s);
	level[s] = 1;
	while(!q.empty()) {
		int u = q.front();
		q.pop();
		for(int i = head[u];~ i;i = nxt[i]) {
			int v = ver[i];
			if(cap[i]&&!level[v]) {
				level[v] = level[u] + 1;
				q.push(v);
			}
		}
	}
	return level[t] > 0;
}
int dfs(int x,int t,int maxflow) {
	if(x == t||!maxflow)return maxflow;
	int flow = 0,f;
	for(int& i = cur[x];~ i;i = nxt[i]) {
		int v = ver[i];
		if(level[v] == level[x] + 1&&(f = dfs(v , t , min(maxflow , cap[i])))) {
			if(!f) {
				level[v] = 0;
				break ;
			}
			flow += f;
			maxflow -= f;
			cap[i] -= f;
			cap[i ^ 1] += f;
		}
	}
	return flow;
}
int Dinic(int s,int t) {
	int flow = 0;
	while(bfs(s , t)) {
		memcpy(cur , head , sizeof(head));
		flow += dfs(s , t , 0x3f3f3f3f);
	}
	return flow;
}
int main() {
	freopen("flyer.in","r",stdin);
	freopen("flyer.out","w",stdout);
	scanf("%d%d",&n,&m);
	memset(head , -1 , sizeof(head));
	int u,v;
	while(~ scanf("%d%d",&u,&v)) {
		add(u , v , 1);
		add(v , u , 0);
	}
	int S = n + 1,T = n + 2;
	for(int i = 1;i <= m;++ i) {
		add(S , i , 1);
		add(i , S , 0);
	}
	for(int i = m + 1;i <= n;++ i) {
		add(i , T , 1);
		add(T , i , 0);
	}
	printf("%d\n",Dinic(S , T));
	fclose(stdin);
	fclose(stdout);
	return 0;
}