HDU 1285 确定比赛名次【拓扑排序】链式向前星+优先队列-白红宇

HDU 1285 确定比赛名次【拓扑排序】链式向前星+优先队列

阅读量：369 次

发布时间：2019-03-04

本文共 1609 字，大约阅读时间需要 5 分钟。

?????????????????????????????????????????????????????????????????????????????????????????

????

????: ?????????????????????????????????????????P1?P2?????????????????????????

????: ????????????????????????????????Kahn???????????????????????DAG??

????: ?Kahn??????????????????0????????????????????????????????????

????:

???????????0?

?????????????????????

????0??????????

????????????????????????

?????????????????

????

#include 
   
    #include 
    
     #include 
     
      #include 
      
       #include 
       
        using namespace std;int main() {    int n, m;    while (true) {        cin >> n >> m;        if (m == 0) break;        vector
        
          in(n + 1, 0); vector
         
           head(n + 1); vector
          
           
            > adj(n + 1); int cnt = 0; for (int i = 1; i <= m; ++i) { int p1, p2; cin >> p1 >> p2; adj[p1].push_back(p2); in[p2]++; } // Initialize the priority queue priority_queue

, greater

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

ans; while (!q.empty()) { int u = q.top(); q.pop(); ans.push_back(u); for (int v : adj[u]) { in[v]--; if (in[v] == 0) q.push(v); } } // Output the result if (ans.size() != n) { // This should not happen as per the problem statement cout << "Error" << endl; } else { for (int i = 0; i < ans.size(); ++i) { if (i > 0) cout << " "; cout << ans[i]; } } } return 0;}

????

????: ????????n???????m????????????????????????

???????: ????????????0?????????????????????

????: ??Kahn???????????????????????????????0?????????

????: ????????????????????

???????????????????????????????????????????

转载地址：http://qlyg.baihongyu.com/

你可能感兴趣的文章

No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?