Create 1774번 우주신과의 교감.java

Author: lamodadite

thursday/week35/haechul/1774번 우주신과의 교감.java

@@ -0,0 +1,88 @@
+package BOJ.boj1774;
+
+import java.util.*;
+
+public class Main {
+    static int[] parent;
+
+    static class Node {
+        int x, y;
+        double w;
+
+        public Node(int x, int y, double w) {
+            this.x = x;
+            this.y = y;
+            this.w = w;
+        }
+    }
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+
+        int n = sc.nextInt(); // 우주신의 개수
+        int m = sc.nextInt(); // 연결된 통로의 개수
+
+        parent = new int[n + 1];
+        for (int i = 1; i <= n; i++) {
+            parent[i] = i;
+        }
+
+        int[][] gods = new int[n + 1][2]; // 우주신들 좌표
+        for (int i = 1; i <= n; i++) {
+            gods[i][0] = sc.nextInt();
+            gods[i][1] = sc.nextInt();
+        }
+
+        for (int i = 0; i < m; i++) {
+            int x = sc.nextInt();
+            int y = sc.nextInt();
+
+            union(x, y);
+        }
+
+        PriorityQueue<Node> pq = new PriorityQueue<>((o1, o2) -> Double.compare(o1.w, o2.w));
+
+        for (int i = 1; i <= n; i++) {
+            for (int j = i + 1; j <= n; j++) {
+                int x1 = gods[i][0];
+                int y1 = gods[i][1];
+                int x2 = gods[j][0];
+                int y2 = gods[j][1];
+
+                double dist = Math.sqrt(Math.pow(x1 - x2, 2) + Math.pow(y1 - y2, 2));
+
+                pq.offer(new Node(i, j, dist));
+            }
+        }
+
+        double result = 0;
+
+        while (!pq.isEmpty()) {
+            Node cur = pq.poll();
+
+            if (union(cur.x, cur.y)) {
+                result += cur.w;
+            }
+        }
+
+        System.out.print(String.format("%.2f", result));
+    }
+
+    public static int find(int x) {
+        if (parent[x] == x) {
+            return x;
+        }
+        return parent[x] = find(parent[x]);
+    }
+    public static boolean union(int x, int y) {
+        int a = find(x);
+        int b = find(y);
+
+        if (a != b) {
+            parent[a] = y;
+            return true;
+        }
+
+        return false;
+    }
+}