HDU 1285 topological_sort

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/**********************************************

      author   :    Grant Yuan
      time     :    2014.7.29
      algorithm:    topological_sort
      source   :    HDU 1285

**********************************************/

#include <iostream>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#define MAX 511
using namespace std;

int mat[MAX][MAX],num[MAX];
int n,m,ans,sum;
int lu[MAX];

int main()
{   int a,b;
    while(~scanf("%d%d",&n,&m)){
        memset(mat,0,sizeof(mat));
        memset(num,0,sizeof(num));
        memset(lu,0,sizeof(lu));
        for(int i=0;i<m;i++)
        {
           scanf("%d%d",&a,&b);
           if(mat[b][a]==0)
           {
               mat[b][a]=1;
               num[b]++;
           }
        }
        int i,p=1;
        while(1){
            for(i=1;i<=n;i++)
            {
                if(num[i]==0)
                    break;
            }
            if(i==n+1)
                break;
                num[i]=-1;

            lu[p++]=i;
            for(int j=1;j<=n;j++)
            {
                if(mat[j][i])
                    num[j]--;
            }
        }
        
        for(int j=1;j<=n;j++)
            if(j<n)printf("%d ",lu[j]);
            else printf("%d",lu[j]);
        printf("\n");
    }
    return 0;
}
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HDU 1285 topological_sort

原文：http://blog.csdn.net/yuanchang_best/article/details/38274151