p1137

不知道哪里错了

代码

#include<bits/stdc++.h>
#define uf(x,y,z) for(int x=y;x<=z;x++)
#define df(x,y,z) for(int x=y;x>=z;x--)
#define int long long 
#define r read()
#define w(x) write(x)
using namespace std;
int dis[100010],st,n,m,x,y;
struct node
{
	int l;
	map<int,int>s;
}a[100010];
int read()
{
	int x=0,t=1;
	char ch=getchar();
	while(ch<'0'||ch>'9')
	{
		if(ch=='-')t=-1;
		ch=getchar();
	}
	while(ch>='0'&&ch<='9')
	{
		x=(x<<1)+(x<<3)+(ch^48);
		ch=getchar();
	}
	return x*t;
} 
void write(int x)
{
	if(x<0)
	{
		putchar('-');
		x=-x;
	}
	if(x>9)write(x/10);
	putchar(x%10+'0');
}
void bfs()
{
	queue<int> q;
	q.push(st);
	while(!q.empty())
	{
		int u=q.front();
		q.pop();
		uf(i,1,a[u].l)
		{
			int v=a[u].s[i];
			if(dis[v]<dis[u]+1)
			{
				dis[v]=dis[u]+1;
				q.push(v);
			}
		}
	}
}
signed main()
{
	n=r;m=r;
	uf(i,1,n)dis[i]=1;
	uf(i,1,m)
	{
		x=r;y=r;
		a[x].s[++a[x].l]=y;
		dis[y]=0;
	}
	uf(i,1,n)
	{
		if(dis[i]==1)st=i;
	}
	bfs();
	uf(i,1,n)
	{
		w(dis[i]);
		putchar('\n');
	}
	return 0;
}