寒假集训日志（二）——最小生成树，拓扑排序，欧拉回路，连通路

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<queue>
#include<vector>
#include<cstring>
using namespace std;

const int maxPoint = 30010;

vector <int> Edge[maxPoint];
int indgree[maxPoint];
int main(){
    int T;
    scanf("%d",&T);
    while( T-- ){
        int n, m;
        int a , b;
        scanf("%d %d",&n,&m);
        memset( indgree , 0 , sizeof(indgree));
        for( int i = 1 ; i<= n ; ++i){
            Edge[i].clear();
        }
        for( int i= 1 ; i<=m ;++i){
                scanf("%d %d",&a,&b);
                Edge[b].push_back(a);
                indgree[a] ++;
        }
       priority_queue <int> q;
        for( int i = 1 ; i<=n; ++i){
            if( indgree[i] == 0)    q.push(i);
        }
      vector <int> res ;
        while( !q.empty()){
            int t = q.top() ;
            res.push_back(t);
             q.pop();
            for( int i = 0 ; i< Edge[t].size() ; ++i){
                int x = Edge[t][i] ;
                indgree[x] --;
                if(indgree[x] == 0 ) {
                    q.push(x);
                }
            }
        }
        for(int i = res.size() -1 ; i>= 0 ; --i){
            if( i == 0) printf("%d", res[i] );
            else    printf("%d ", res[i]);
        }
        puts("");
    }
return 0;
}

 1 vector <int> ans;
 2 
 3 void dfs(int u) {
 4     if(u没有路可以继续下去) ans.push_back(u);
 5     else {
 6         for(e 是 u 出发的边) {
 7             delete e;
 8             dfs(e.to);
 9         }
10     }
11 }
12 
13 void getEuler() {
14     int start;
15     for(start=1;start<=N;++start)
16         if(degree(start)%2==1)
17             break;
18     if(start==N+1) start=1;
19 
20     dfs(start);
21     ans.reverse();        // ans反向。
22 }