16-g0rnn

g0rnn/README.md

@@ -17,4 +17,7 @@
 | 13차시 | 2025.01.05 |  백트래킹   |             [스타트와 링크](https://www.acmicpc.net/problem/14889)              | https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/52 |
 
 
+| 16차시 | 2025.01.18 |  다익스트라   |             [최단경로](https://www.acmicpc.net/problem/1753)              | https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/62 |
+
+
 ---

g0rnn/dijkstra/16-g0rnn.cpp

@@ -0,0 +1,50 @@
+//
+// Created by 김균호 on 2025. 1. 18..
+//
+#include <iostream>
+#include <vector>
+#include <queue>
+#include <climits>
+using namespace std;
+
+int v, e, s;
+int a, b, w;
+vector<vector<pair<int, int>>> graph;
+priority_queue<pair<int, int>> pq; // { weight, node }
+vector<int> dist(v+1, INT_MAX);
+
+// pq의 공간 복잡도는 O(E)
+void dijkstra() {
+	dist = vector<int>(v+1, INT_MAX);
+	dist[s] = 0;
+	pq.emplace(0, s);
+
+	while(!pq.empty()) {
+		int d = -pq.top().first; // 음수로 저장되어 있음 -> 최소 우선순위 큐
+		int cur = pq.top().second; pq.pop();
+
+		if (dist[cur] < d) continue;
+		for(auto& [adj, wei] : graph[cur]) {
+			//relax
+			if (d + wei < dist[adj]) {
+				dist[adj] = d + wei;
+				pq.emplace(-d - wei, adj);
+			}
+		}
+	}
+}
+
+int main() {
+	cin >> v >> e >> s;
+	graph = vector<vector<pair<int, int>>>(v+1);
+	for(int i=0;i<e;i++) {
+		cin>>a>>b>>w;
+		graph[a].emplace_back(b, w);
+	}
+	dijkstra();
+	for (int i=1;i<dist.size();i++) {
+		if (dist[i] == INT_MAX) cout<<"INF\n";
+		else cout<<dist[i]<<'\n';
+	}
+	return 0;
+}