From 85564c5192ca0196da90866db6ed7d785d230be6 Mon Sep 17 00:00:00 2001
From: lkhyun <102892446+lkhyun@users.noreply.github.com>
Date: Mon, 30 Jun 2025 20:54:19 +0900
Subject: [PATCH] =?UTF-8?q?[20250630]=20BOJ=20/=20G4=20/=20=EC=82=AC?=
 =?UTF-8?q?=EC=9D=B4=ED=81=B4=20=EA=B2=8C=EC=9E=84=20/=20=EC=9D=B4?=
 =?UTF-8?q?=EA=B0=95=ED=98=84?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 ...4\355\201\264 \352\262\214\354\236\204.md" | 58 +++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 "lkhyun/202506/30 BOJ G4 \354\202\254\354\235\264\355\201\264 \352\262\214\354\236\204.md"

diff --git "a/lkhyun/202506/30 BOJ G4 \354\202\254\354\235\264\355\201\264 \352\262\214\354\236\204.md" "b/lkhyun/202506/30 BOJ G4 \354\202\254\354\235\264\355\201\264 \352\262\214\354\236\204.md"
new file mode 100644
index 00000000..56ce693b
--- /dev/null
+++ "b/lkhyun/202506/30 BOJ G4 \354\202\254\354\235\264\355\201\264 \352\262\214\354\236\204.md"	
@@ -0,0 +1,58 @@
+```java
+import java.util.*;
+import java.io.*;
+
+public class Main{
+    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    static StringTokenizer st;
+    static int n,m;
+    static int[] parent;
+
+    public static void main(String[] args) throws Exception{
+        st = new StringTokenizer(br.readLine());
+        n = Integer.parseInt(st.nextToken());
+        m = Integer.parseInt(st.nextToken());
+
+        parent = new int[n];
+        for (int i = 0; i < n; i++) {
+            parent[i] = i;
+        }
+
+        int ans = 0;
+        for (int i = 1; i <= m; i++) {
+            st = new StringTokenizer(br.readLine());
+            int a = Integer.parseInt(st.nextToken());
+            int b = Integer.parseInt(st.nextToken());
+            if(union(a,b)){
+                ans = i;
+                break;
+            }
+        }
+        bw.write(ans+"");
+        bw.close();
+    }
+    static int find(int cur){
+        if(cur == parent[cur]){
+            return cur;
+        }else{
+            return parent[cur] = find(parent[cur]);
+        }
+    }
+    static boolean union(int a, int b){
+        int rootA = find(a);
+        int rootB = find(b);
+
+        if(rootA == rootB){
+            return true;
+        }else{
+            if(rootA < rootB){
+                parent[rootA] = rootB;
+            }else{
+                parent[rootB] = rootA;
+            }
+            return false;
+        }
+    }
+}
+```