算法分析:
1)反向拓扑排序+优先队列
http://www.cppblog.com/Davidlrzh/articles/115620.html
2)原题
http://poj.org/problem?id=3687
#include<cstdio>
#include <cstring>
#define MAX 201
bool TopoSort(int (&into)[MAX],int(&map)[MAX][MAX],int(&topo)[MAX],int n){
int i,j,k;
for(i=n;i>=1;i--){
j=n;
while(into[j]!=0){//找入度为零的点
j--;
if(j<1)
return false;
}
topo[j]=i;
into[j]=-1;
for(k=1;k<=n;k++){//找到后,将所有与j点相邻的点的入度减1
if(map[j][k])
into[k]--;
}
}
return true;
}
int main(){
int count,into[MAX],topo[MAX],map[MAX][MAX];
scanf("%d",&count);
while(count--){
int n,m,i,a,b;
scanf("%d%d",&n,&m);
memset(map,0,sizeof(map));
memset(into,0,sizeof(into));
memset(topo,0,sizeof(topo));
for(i=0;i<m;i++){
scanf("%d%d",&a,&b);
if(!map[b][a]){
map[b][a]=1;
into[a]++;
}
}
if(TopoSort(into,map,topo,n)){
for(i=1;i<n;i++)
printf("%d ",topo[i]);
printf("%d\n",topo[i]);
}
else printf("-1\n");
}
return 0;
}