acm专题---拓扑排序+优先队列

#include<iostream>
#include<algorithm>
#include<vector>
#include<string>
#include<stack>
#include<fstream>
#include<queue>
#include<string.h>
#include<list>
#include<map>
using namespace std;
const int maxnum = 501;
bool graph[maxnum][maxnum];
int in[maxnum];
struct cmp
{
	bool operator()(int a, int b)
	{
		return a > b;
	}
};
int main()
{
	int n, m;
	while (cin >> n >> m)
	{

		memset(graph, false, sizeof(graph));
		memset(in, 0, sizeof(in));

		for (int i = 0; i < m; i++)
		{
			int x, y;
			cin >> x >> y;
			if (graph[x][y])
				continue;
			graph[x][y] = true;
			in[y]++;
		}
		priority_queue<int, vector<int>, cmp> myque;
		for (int i = 1; i <= n; i++)
		{
			if (in[i] == 0)
				myque.push(i);
		}
		int cnt = 0;
		while (!myque.empty())
		{
			int tmptop = myque.top();
			cnt++;
			if (cnt != n)
				cout << tmptop << " ";
			else cout << tmptop << endl;
			myque.pop();
			in[tmptop] = -1;
			for (int i = 1; i <= n; i++)
			{
				if (graph[tmptop][i])
				{
					in[i]--;
					if (in[i] == 0)
						myque.push(i);
				}
			}
		}
	}
	return 0;
}
/*
5 3
1 4
4 3
2 5

1 2 4 3 5
*/