拓扑排序 HDU1285

#include <stdio.h>
#include<iostream>
#include <string.h>
using namespace std;
const int N = 1000;
int n, m;
int Map

;
int topNum
;
bool toposort(int *ret)
{
int Indegree
;
memset(Indegree, 0, sizeof(Indegree));
int k = 0;
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++)
Indegree[i] += Map[j][i];//计算入度，没有边的时候Map[j][i]为0
for (int i = 1; i <= n; i++)
{
for (int j = 1; j <= n; j++)
{
if (Indegree[j] == 0)
{
--Indegree[j];
ret[k++] = j;
for (int t = 1; t <= n; t++)
if (Map[j][t])
Indegree[t]--;
break;
}
}

}
if (k == n)
return true;
return false;
}
int main()
{
int a, b;
while (cin >> n >> m)
{
memset(Map, 0, sizeof(Map));
for (int i = 0; i < m; i++)
{
cin >> a >> b;
Map[a][b] = 1;
}
toposort(topNum);
for (int i = 0; i < n; i++)
{
if (i == n - 1)
printf("%d\n", topNum[i]);
else
printf("%d ", topNum[i]);
}
}

return 0;
}