网络流最大匹配dfs求增广路裸的代码

include <iostream>

include <cstdio>

include <cstring>

using namespace std;
int head[10202],match[10202];
bool used[10202];
int x,y;
int V,k;
int inde,n,m;
struct path{
int to,next;
}edge[40002];
void add(int x,int y){
edge[++inde].to = y;
edge[inde].next = head[x];
head[x] = inde;
}
bool dfs(int u){
used[u] = true;
for(int i = head[u];i;i = edge[i].next){
int v = edge[i].to,w = match[v];
if(w < 0 || !used[w] && dfs(w)){
match[u] = v;
match[v] = u;
return true;
}
}
return false;
}
int er(){
V = n * 2;
int ans = 0;
memset(match,-1,sizeof(match));
for(int v = 1;v <= V;v++){
if(match[v] < 0){
memset(used,0,sizeof(used));
if(dfs(v)){
ans++;
}
}
}
return ans;
}
int main(){
scanf("%d %d",&n,&k);
for(int i = 1;i <= k;i++){
scanf("%d %d",&x,&y);
add(x, n + y);
}
printf("%d\n",er() * 13);
}