acmTrain DAG C

/*
kliorange
2016.01.23
Directed Acyclic Graph C
http://acm.hust.edu.cn/vjudge/contest/viewSource.action?id=5333723
*/

#include <stdio.h>
#include <cstring>
#define MAXN 505

int N = 0, M = 0, order = 0;
int map[MAXN][MAXN];
int in[MAXN];
int num[MAXN];

int	findPoint()
{
	for (int i = 1; i<=N; i++)
	{
		if (in[i] == 0)
		{
			num[order] = i;
			order++;
			in[i]--;
			return i;
		}
	}
}

void deleteLine(int t)
{
	for (int i = 1; i <= N; i++)
	{
		if (map[t][i]!=0)
		{
			in[i] -- ;
		}
		map[t][i] = 0;
	}
	return ;
}

void topu()
{
	int k;
	for (int i = 0; i<N; i++)
	{
		k = findPoint();
		deleteLine(k);
	}
	return;
}

int main()
{
	int a = 0, b = 0;
	while (scanf("%d %d", &N, &M) != EOF)
	{
		order = 0;
		memset(num, 0, sizeof(num));
		memset(map, 0, sizeof(map));
		memset(in, 0, sizeof(in));
		for (int k = 0; k < M; k++)
		{
			scanf("%d %d", &a, &b);
			if (map[a][b]==0)
			{
				map[a][b]++;
				in[b]++;
			}
		}
		topu();
		for (int i = 0; i < N - 1; i++)
		{
			printf("%d", num[i]);
			printf(" ");
		}
		printf("%d", num[N - 1]);
		printf("\n");
	}
	return 0;
}