19-dohyeondol1

dohyeondol1/README.md

@@ -18,4 +18,6 @@
  | 14차시 | 2025.05.16 |  힙  | [더 맵게](https://school.programmers.co.kr/learn/courses/30/lessons/42626)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/54|
  | 15차시 | 2025.05.22 |  DFS  | [석유 시추](https://school.programmers.co.kr/learn/courses/30/lessons/250136)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/60|
  | 16차시 | 2025.05.24 |  BFS  | [토마토](https://www.acmicpc.net/problem/7576)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/61|
- | 17차시 | 2025.06.26 |  기하학  | [선분 교차 2](https://www.acmicpc.net/problem/17387)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/65|
+ | 17차시 | 2025.06.26 |  기하학  | [선분 교차 2](https://www.acmicpc.net/problem/17387)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/65|
+ | 18차시 | 2025.07.04 |  기하학  | [Water Testing](https://www.acmicpc.net/problem/16057)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/70|
+ | 19차시 | 2025.07.09 |  그래프 이론  | [최소 스패닝 트리](https://www.acmicpc.net/problem/1197)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/76|

dohyeondol1/그래프 이론/19-dohyeondol1.cpp

@@ -0,0 +1,51 @@
+#include <iostream>
+#include <vector>
+#include <queue>
+#include <utility>
+using namespace std;
+
+int prim(int V, const vector<vector<pair<int, int>>>& adj) {
+    vector<bool> visited(V, false);
+    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<>> pq;
+
+    int totalWeight = 0;
+    pq.push({0, 0});
+
+    while(!pq.empty()) {
+        auto [weight, u] = pq.top();
+        pq.pop();
+
+        if(visited[u]) continue;
+        visited[u] = true;
+        totalWeight += weight;
+
+        for(auto& [w, v] : adj[u]) {
+            if(!visited[v]) {
+                pq.push({w, v});
+            }
+        }
+    }
+
+    return totalWeight;
+}
+
+int main() {
+    cin.tie(nullptr)->sync_with_stdio(false);
+
+    int V, E;
+    cin >> V >> E;
+    vector<vector<pair<int, int>>> adj(V);
+
+    for(int i = 0; i < E; ++i) {
+        int A, B, C;
+        cin >> A >> B >> C;
+
+        A--; B--;
+        adj[A].push_back({C, B});
+        adj[B].push_back({C, A});
+    }
+
+    int mstWeight = prim(V, adj);
+    cout << mstWeight << '\n';
+    return 0;
+}