BOJ_1647 : 도시 분할 계획

Author: spring0913

week8/BOJ_1647(도시 분할 계획).java

@@ -0,0 +1,58 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    public static int[] parent;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        int N = Integer.parseInt(st.nextToken());
+        int M = Integer.parseInt(st.nextToken());
+        parent = new int[N+1];
+        for(int i=1; i<=N; i++) {
+            parent[i] = i;
+        }
+        PriorityQueue<int[]> pq = new PriorityQueue<>((o1, o2) -> Integer.compare(o1[2], o2[2]));
+        for(int i=0; i<M; i++) {
+            st = new StringTokenizer(br.readLine());
+            int A = Integer.parseInt(st.nextToken());
+            int B = Integer.parseInt(st.nextToken());
+            int C = Integer.parseInt(st.nextToken());
+            pq.offer(new int[]{A, B, C});
+        }
+        long totalCost = 0;
+        int maxCost = 0;
+        while(!pq.isEmpty()) {
+            int[] edge = pq.poll();
+            int v1 = edge[0];
+            int v2 = edge[1];
+            int cost = edge[2];
+
+            // 사이클이 없으면 연결 후 비용 더하기
+            if(union(v1, v2)) {
+                totalCost += cost;
+                maxCost = cost;
+            }
+        }
+        System.out.println(totalCost - maxCost);
+    }
+
+    public static int find(int x) {
+        if(parent[x] == x) {
+            return x;
+        }
+        parent[x] = find(parent[x]);
+        return parent[x];
+    }
+
+    public static boolean union(int x, int y) {
+        x = find(x);
+        y = find(y);
+        if(x == y) {
+            return false;
+        }
+        parent[y] = x;
+        return true;
+    }
+}