From 05d0f9adeac7c3c0639ba6d79bbfef7dfc498a53 Mon Sep 17 00:00:00 2001
From: sukangpunch <popora99@naver.com>
Date: Fri, 30 Jan 2026 20:47:19 +0900
Subject: [PATCH] =?UTF-8?q?[Week04]=20BOJ=5F4386:=20=EB=B3=84=EC=9E=90?=
 =?UTF-8?q?=EB=A6=AC=20=EB=A7=8C=EB=93=A4=EA=B8=B0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../sukangpunch.java"                         | 104 ++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 "weekly/week04/BOJ_4386_\353\263\204\354\236\220\353\246\254\353\247\214\353\223\244\352\270\260/sukangpunch.java"

diff --git "a/weekly/week04/BOJ_4386_\353\263\204\354\236\220\353\246\254\353\247\214\353\223\244\352\270\260/sukangpunch.java" "b/weekly/week04/BOJ_4386_\353\263\204\354\236\220\353\246\254\353\247\214\353\223\244\352\270\260/sukangpunch.java"
new file mode 100644
index 0000000..5ca60a2
--- /dev/null
+++ "b/weekly/week04/BOJ_4386_\353\263\204\354\236\220\353\246\254\353\247\214\353\223\244\352\270\260/sukangpunch.java"
@@ -0,0 +1,104 @@
+package study.week04;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.PriorityQueue;
+
+// 별자리 만들기
+public class BOJ_4386 {
+
+    static class Point{
+        int num;
+        double x;
+        double y;
+
+        public Point(int num, double x,double y){
+            this.num = num;
+            this.x = x;
+            this.y = y;
+        }
+    }
+
+    static class Edge{
+        int start;
+        int end;
+        double weight;
+
+        public Edge(int start, int end, double weight){
+            this.start = start;
+            this.end = end;
+            this.weight = weight;
+        }
+    }
+
+    static int[] parent;
+    static PriorityQueue<Edge> pq;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        int N = Integer.parseInt(br.readLine());
+        Point [] points = new Point[N];
+
+        for(int i=0; i<N; i++){
+            String [] s = br.readLine().split(" ");
+            double x = Float.parseFloat(s[0]);
+            double y = Float.parseFloat(s[1]);
+
+            points[i] = new Point(i, x,y);
+        }
+
+        pq = new PriorityQueue<>((e1, e2) -> {
+            if(e1.weight < e2.weight) return -1;
+            return 1;
+        });
+
+        for (int i=0; i<N; i++){
+            for (int j = i+1; j<N; j++){
+                double weight = distance(points[i], points[j]);
+                pq.add(new Edge(points[i].num, points[j].num, weight));
+            }
+        }
+
+        parent = new int[N];
+        for(int i=0; i<N; i++){
+            parent[i] = i;
+        }
+
+        double ans = 0;
+
+        while(!pq.isEmpty()){
+            Edge edge = pq.poll();
+            int start = edge.start;
+            int end = edge.end;
+            double cost = edge.weight;
+
+            if(find(start) != find(end)){
+                ans += cost;
+                union(start, end);
+            }
+        }
+
+        System.out.println(ans);
+
+    }
+
+    public static void union(int x, int y){
+        int rootA = find(x);
+        int rootB = find(y);
+        parent[Math.min(rootA, rootB)] = Math.max(rootA, rootB);
+    }
+
+    private static int find(int x) {
+        if(x != parent[x]){
+            parent[x] = find(parent[x]);
+        }
+
+        return parent[x];
+    }
+
+    private static double distance(Point p1, Point p2) {
+        return Math.sqrt(Math.pow(p1.x - p2.x, 2) + Math.pow(p1.y - p2.y, 2));
+    }
+}