bzoj1191: [HNOI2006]超级英雄Hero

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int read()
{
char ch=getchar();int f=0;
while(ch<'0'||ch>'9') ch=getchar();
while(ch>='0'&&ch<='9')
{f=(f<<1)+(f<<3)+ch-'0';
ch=getchar();}
return f;
}
int n,m,tot,head[1005];
struct node
{
int from;
int to;
int next;
}edge[4005];
void add(int u,int v)
{
edge[tot].from=u;
edge[tot].to=v;
edge[tot].next=head[u];
head[u]=tot++;
}
bool vis[1005];int lk[1005];
bool find(int x)
{
for(int i=head[x];i!=-1;i=edge[i].next)
{
int v=edge[i].to;
if(!vis[v])
{
vis[v]=1;
if(lk[v]==-1||find(lk[v]))
{
lk[v]=x;
return 1;
}
}
}
return 0;
}
int main()
{
memset(head,-1,sizeof(head));
memset(lk,-1,sizeof(lk));
n=read();m=read();int x,y;
for(int i=1;i<=m;i++)
{
x=read();y=read();
add(i,x);
add(i,y);
memset(vis,0,sizeof(vis));
if(!find(i))
{
printf("%d",i-1);
return 0;
}
}
printf("%d",m);
return 0;
}