确定比赛名次 HDU

 

 注意点： 输入数据中可能有重复，需要进行处理！

#include <stdio.h>
#include <iostream>
#include <cstring>
#include <vector>
#include <algorithm>
#include <sstream>


using namespace std;

int n, m;

int g[501][501];    
int indegree[501];    // 入度 
int r[501];

int main()
{
    while(scanf("%d %d", &n, &m) != EOF)
    {
        memset(g, 0, sizeof(g));
        memset(indegree, 0, sizeof(indegree));

        for(int i = 1; i <= m; ++i)
        {
            int a, b;
            scanf("%d %d", &a, &b);
            if(g[a][b] == 0)    // 输入数据中可能有重复输入！！！ 
            {
                g[a][b] = 1;
                indegree[b]++;
            }
        }

        for(int k = 1; k <= n; ++k)
        {
            int i, j;
            for(i = 1; i <= n; ++i)
            {
                if(indegree[i] == 0)
                {
                    indegree[i] = -1;
                    r[k] = i;
                    break;
                }
            }

            for(j = 1; j <= n; ++j)
            {
                if(g[i][j] == 1)
                {
                    g[i][j] = 0;
                    indegree[j]--;
                }
            }
        }

        for(int i = 1; i < n; ++i)
            cout << r[i] << ' ';
        cout << r[n] << endl;
    }


    return 0;
}