UVa 10305 Ordering Tasks【拓扑排序】

题意：给出n件事情，m个二元组关系，求它们的拓扑序列

用的队列来做

 #include<iostream>
 #include<cstdio>
 #include<cstring>
 #include <cmath>
 #include<stack>
 #include<vector>
 #include<map>
 #include<set>
 #include<queue>
 #include<algorithm>
 using namespace std;

 #define foreach(i,c) for (__typeof(c.begin()) i = c.begin(); i != c.end(); ++i)

 typedef long long LL;
 const int INF = (<<)-;
 const int mod=;
 const int maxn=;
 int ecnt;
 int n,m;

 int g[][],in[],ans[maxn];

 void toposort(){
     queue<int> q;

     for(int i=;i<=n;i++)
     if(in[i]==) q.push(i);

     int cnt=;
     while(!q.empty()){
         int tmp=q.front();q.pop();
         ans[++cnt]=tmp;

         for(int j=;j<=n;j++){
             if(g[tmp][j]){
                 in[j]--;
                 if(in[j]==) q.push(j);
             }
         }
     }

     printf("%d",ans[]);
     for(int i=;i<=cnt;i++)
     printf(" %d",ans[i]);
     printf("\n");
 }

 int main(){
     while(scanf("%d %d",&n,&m)!=EOF){
         if(n==&&m==) break;

         memset(g,,sizeof(g));
         memset(in,,sizeof(in));

         while(m--){
             int u,v;
             cin>>u>>v;
             g[u][v]=;
             in[v]++;
         }
         toposort();
     }
     return ;
 }