BestCoder #1-1 HDU 4857 逆拓扑排序

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//
//  main.cpp
//  HDU 4857 拓扑排序
//
//  Created by 郑喆君 on 8/9/14.
//  Copyright (c) 2014 itcast. All rights reserved.
//#include<cstdio>
#include<cstring>
#include<iostream>
#include<iomanip>
#include<queue>
#include<cmath>
#include<stack>
#include<map>
#include<vector>
#include<set>
#include<algorithm>
using namespace std;
typedef long long LL;
const int int_max = 0x07777777;
const int int_min = 0x80000000;
const int maxn = 31000;
struct cmp {bool operator()(int a, int b){return a < b;}
};
vector<int> g[maxn];
int cnt[maxn];
int n,m;
int main(int argc, const char * argv[])
{int t;scanf("%d", &t);while(t--){scanf("%d %d", &n, &m);for(int i = 1; i <= n; i++) g[i].clear();memset(cnt, 0, sizeof(cnt));for(int i = 0; i < m; i++){int x,y;scanf("%d %d", &x, &y);g[y].push_back(x);cnt[x]++;}priority_queue<int, vector<int>, cmp> q;for(int i = 1; i <= n; i++) if(!cnt[i]) q.push(i);vector<int> res;while (!q.empty()) {int u = q.top();q.pop();res.push_back(u);for(int i = 0; i < g[u].size(); i++) if(--cnt[g[u][i]] == 0) q.push(g[u][i]);}if(n==1){printf("%d\n", 1);}else{for(int i = res.size()-1; i > 0; i--) printf("%d ", res[i]);printf("%d\n", res[0]);}}}

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