[20260128] BOJ / G3 / Traveling SCCC President / 한종욱

Author: Ukj0ng

Ukj0ng/202601/28 BOJ G3 Traveling SCCC President.md

@@ -0,0 +1,96 @@
+```
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    private static final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    private static final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    private static PriorityQueue<Edge> pq;
+    private static int[] uf, size;
+    private static int N, M, S;
+
+    public static void main(String[] args) throws IOException {
+        init();
+
+        int answer = kruskal();
+
+        bw.write(answer + "\n");
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+
+    private static void init() throws IOException {
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        N = Integer.parseInt(st.nextToken());
+        M = Integer.parseInt(st.nextToken());
+        S = Integer.parseInt(st.nextToken());
+
+        pq = new PriorityQueue<>((o1, o2) -> Integer.compare(o1.w, o2.w));
+        uf = new int[N+1];
+        size = new int[N+1];
+
+        for (int i = 1; i <= N; i++) {
+            uf[i] = i;
+            size[i] = 1;
+        }
+
+        for (int i = 1; i <= M; i++) {
+            st = new StringTokenizer(br.readLine());
+            int u = Integer.parseInt(st.nextToken());
+            int v = Integer.parseInt(st.nextToken());
+            int w = Integer.parseInt(st.nextToken());
+
+            pq.add(new Edge(u, v, w));
+        }
+
+        st = new StringTokenizer(br.readLine());
+    }
+
+    private static int kruskal() {
+        int cost = 0;
+        int count = 0;
+
+        while (!pq.isEmpty() && count < N-1) {
+            Edge current = pq.poll();
+
+            int root1 = find(current.u);
+            int root2 = find(current.v);
+            if (root1 == root2) continue;
+            union(root1, root2);
+            cost += current.w;
+            count++;
+        }
+
+        return cost;
+    }
+
+    private static void union(int x, int y) {
+        if (size[x] < size[y]) {
+            uf[x] = y;
+            size[y] += size[x];
+        } else {
+            uf[y] = x;
+            size[x] += size[y];
+        }
+    }
+
+    private static int find(int x) {
+        if (uf[x] == x) return x;
+
+        return uf[x] = find(uf[x]);
+    }
+
+    static class Edge {
+        int u;
+        int v;
+        int w;
+
+        public Edge(int u, int v, int w) {
+            this.u = u;
+            this.v = v;
+            this.w = w;
+        }
+    }
+}
+```