SGU 230 拓扑排序

#include <stdio.h>
#include <iostream>
#include <queue>
#include <algorithm>
#include <map>
#include <vector>
#include <cmath>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <fstream>
#include <set>
#include <stack>
#include <list>
using namespace std;

#define READ freopen("acm.in","r",stdin)
#define WRITE freopen("acm.out","w",stdout)
#define ll long long
#define ull unsigned long long
#define uint unsigned int
#define PII pair<int,int>
#define PDD pair<double,double>
#define fst first
#define sec second
#define MS(x,d) memset(x,d,sizeof(x))
#define INF 0x3f3f3f3f
#define ALL(x) x.begin(),x.end()
#define PB push_back
#define MOD 99991
#define MAX 1000000

int n,m;
vector<int> G[20000];
vector<int> topo;

bool judge()
{
int du[20000];
int cnt=0;
queue<int> q;
MS(du,0);

for(int i=1;i<=n;i++)
for(int j=0;j<G[i].size();j++)
du[G[i][j]]++;

for(int i=1;i<=n;i++)
if(!du[i])
q.push(i),topo.push_back(i);

cnt+=q.size();

while(!q.empty())
{
int u=q.front();
q.pop();
for(int i=0;i<G[u].size();i++)
{
int v=G[u][i];
du[v]--;
if(!du[v])
q.push(v),cnt++,topo.push_back(v);
}
}
return cnt==n;
}

int main()
{
READ;
scanf("%d%d",&n,&m);
for(int i=0;i<m;i++)
{
int f,t;
scanf("%d%d",&f,&t);
G[f].push_back(t);
}
int ans[20000];
if(judge())
{
for(int i=1;i<=n;i++)
ans[topo[i-1]]=i;
for(int i=1;i<=n;i++)
{
cout<<ans[i];//<<" ";
if(i!=n)
cout<<" ";
}
cout<<endl;
}
else
puts("No solution");
return 0;
}