HDU 1285 确定比赛名次（字典序最小的拓扑排序）

#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
#include <climits>
#include <cmath>
#include <ctime>
#include <vector>
#include <queue>
#include <cassert>
#define IOS ios_base::sync_with_stdio(0); cin.tie(0);
using namespace std;
typedef long long ll;
const int MAX_N = 510;

vector<int> vec[MAX_N];
priority_queue<int, vector<int>, greater<int> > que;
int degree[MAX_N], ans[MAX_N];

void TopoSort(int n)
{
while(!que.empty()) que.pop();
for(int i = 1; i <= n; ++i) {
if(degree[i] == 0) que.push(i);
}
int step = 1;
while(!que.empty()) {
int cur = que.top();
que.pop();
ans[step++] = cur;
for(int i = 0; i < vec[cur].size(); ++i) {
int to = vec[cur][i];
degree[to]--;
if(degree[to] == 0) que.push(to);
}
}
for(int i = 1; i <= n; ++i) {
printf("%d", ans[i]);
if(i < n) printf(" ");
else printf("\n");
}
}

int main()
{
int n, m;
while(~scanf("%d%d", &n, &m)) {
for(int i = 1; i <= n; ++i) { vec[i].clear(); }
memset(degree, 0, sizeof(degree));
for(int i = 0; i < m; ++i) {
int u, v;
scanf("%d%d", &u, &v);
degree[v]++;
vec[u].push_back(v);
}
TopoSort(n);
}
return 0;
}