1272: 确定比赛名次

http://tjuacm.chaosheng.top/problem.php?id=1272
https://vjudge.net/problem/HDU-1285
参考 https://blog.csdn.net/red_red_red/article/details/84329559

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <queue>

using namespace std;

const int N = 510;

int n, m;
int vis[N];
int indegree[N];
int map[N][N];

void tuopu(){
    // 维护入度为0的节点，编号从小到大排序，保证编号小的节点的拓扑序小
    priority_queue<int,vector<int>,greater<int> >q;//优先级队列 

    for(int i = 1; i <= n; i++){
        if(indegree[i] == 0){
            q.push(i);
        } 
    }

    bool temp = false;//控制空格
    while(q.size()){
        int top = q.top();
        q.pop();
        indegree[top]--; //已经输出的数，入度置为-1

        if(!temp)
            printf("%d",top);
        else
            printf(" %d",top); 
        temp = true;

        for(int i = 1; i <= n; i++){
            if(map[top][i]){//与刚才输出的数，有关系的，入度-- 
                indegree[i]--;
                if(!indegree[i]){
                    q.push(i); //如果成了0；进队 
                }
            }
        }        
    }
    printf("\n");
}

int main(){
    int a, b;
    while(cin >> n >> m){
        int f = 1;
        memset(map, 0, sizeof(map));
        memset(indegree, 0, sizeof(indegree));
        for(int i = 1; i <= m; i++){
            cin >> a >> b;
            if(map[a][b] == 0){
                map[a][b] = 1;
                indegree[b]++;
            }
        }

        tuopu();
    }
    return 0;
}