[20260209] BOJ / G4 / 전력난 / 이준희

JHLEE325/202602/09 BOJ G4 전력난.md

@@ -0,0 +1,79 @@
+```java
+import java.io.*;
+import java.util.*;
+
+class Edge implements Comparable<Edge> {
+    int u, v, weight;
+
+    public Edge(int u, int v, int weight) {
+        this.u = u;
+        this.v = v;
+        this.weight = weight;
+    }
+
+    @Override
+    public int compareTo(Edge o) {
+        return this.weight - o.weight;
+    }
+}
+
+public class Main {
+
+    static int[] parent;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st;
+
+        while (true) {
+            st = new StringTokenizer(br.readLine());
+            int m = Integer.parseInt(st.nextToken());
+            int n = Integer.parseInt(st.nextToken());
+
+            if (m == 0 && n == 0) break;
+
+            List<Edge> edges = new ArrayList<>();
+            long totalCost = 0;
+
+            for (int i = 0; i < n; i++) {
+                st = new StringTokenizer(br.readLine());
+                int u = Integer.parseInt(st.nextToken());
+                int v = Integer.parseInt(st.nextToken());
+                int w = Integer.parseInt(st.nextToken());
+                edges.add(new Edge(u, v, w));
+                totalCost += w;
+            }
+
+            Collections.sort(edges);
+
+            parent = new int[m];
+            for (int i = 0; i < m; i++) parent[i] = i;
+
+            long mstCost = 0;
+            int count = 0;
+
+            for (Edge edge : edges) {
+                if (find(edge.u) != find(edge.v)) {
+                    union(edge.u, edge.v);
+                    mstCost += edge.weight;
+                    count++;
+                    if (count == m - 1) break;
+                }
+            }
+
+            System.out.println(totalCost - mstCost);
+        }
+    }
+
+    static int find(int x) {
+        if (parent[x] == x) return x;
+        return parent[x] = find(parent[x]);
+    }
+
+    static void union(int x, int y) {
+        x = find(x);
+        y = find(y);
+        if (x != y) parent[y] = x;
+    }
+}
+```