BOJ_16398 : 행성 연결

Author: spring0913

week8/BOJ_16398(행성 연결).java

@@ -0,0 +1,55 @@
+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));
+        int N = Integer.parseInt(br.readLine());
+        parent = new int[N];
+        PriorityQueue<int[]> pq = new PriorityQueue<>((o1, o2) -> Integer.compare(o1[2], o2[2]));
+        for(int i=0; i<N; i++) {
+            parent[i] = i;
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            for(int j=0; j<N; j++) {
+                int cost = Integer.parseInt(st.nextToken());
+                if(i < j) {
+                    pq.add(new int[]{i, j, cost});
+                }
+            }
+        }
+
+        long minCost = 0;
+        while(!pq.isEmpty()) {
+            int[] edge = pq.poll();
+            int v1 = edge[0];
+            int v2 = edge[1];
+            int cost = edge[2];
+
+            if(union(v1, v2)) {
+                minCost += cost;
+            }
+        }
+        System.out.println(minCost);
+    }
+
+    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;
+    }
+}