[문제해결기법] ALGOSPOT ORDERING ("발표 순서"를 풀기 위한 기초)

algospot ORDERING : https://algospot.com/judge/problem/read/ORDERING

priority_queue로 풀었어야 했는데 queue로 풀어서

30분도 안걸려 풀 문제를 1시간에 걸쳐 돌아왔다

코드는 매우 간단하다

#include <iostream> #include <fstream> #include <vector> #include <queue> #include <algorithm> #include <functional> using namespace std; vector<vector<int>> graph; vector<int> indegree; priority_queue<int, vector<int>, greater<int>> memory; void main_function() { for (int j = 0; j < indegree.size(); j++) { if (indegree[j] == 0) memory.push(j); } while (!memory.empty()) { int node_num = memory.top(); memory.pop(); cout << char(node_num + 'A'); for (int j = 0; j < graph[node_num].size(); j++) { indegree[graph[node_num][j]]--; if (indegree[graph[node_num][j]] == 0) { memory.push(graph[node_num][j]); } } } cout << endl; } int main() { int for_count, alphabet_count, connection_count; char start_char, end_char; cin >> for_count; while (for_count--) { cin >> alphabet_count; graph = vector<vector<int>>(alphabet_count); indegree = vector<int>(alphabet_count, 0); cin >> connection_count; for (int j = 0; j < connection_count; j++) { cin >> start_char >> end_char; graph[start_char - 'A'].push_back(end_char - 'A'); indegree[end_char - 'A']++; } main_function(); } }

이 문제의 일부분만 바꿔 발표 순서를 풀면 쉽게 풀린다.