Ordering Tasks
#include<cstdio>
#include<algorithm>
#include<cstring>
const int maxn=110;
int c[maxn],topo[maxn],t,n,G[maxn][maxn];
bool dfs(int u){
c[u]=-1;
for(int v=1;v<=n;v++)
if(G[u][v]){
if(c[v]<0) return false;
else if(!c[v]&&!dfs(v)) return false;
}
c[u]=1;
topo[--t]=u;
return true;
}
bool toposort(){
t=n;
memset(c,0,sizeof(c));
for(int i=1;i<=n;i++)
if(!c[i]&&!dfs(i)) return false;
return true;
}
int main()
{
int m;
while(scanf("%d%d",&n,&m),n||m){
int u,v;
memset(G,0,sizeof(G));
for(int i=0;i<m;i++){
scanf("%d%d",&u,&v);
G[u][v]=1;
}
if(toposort())
for(int i=0;i<n;i++){
if(i!=0) printf(" ");
printf("%d",topo[i]);
}
printf("\n");
}
return 0;
}UVa 10305 - Ordering Tasks【拓扑排序】
原文地址:http://blog.csdn.net/a995549572/article/details/46538973