Merge pull request #2023 from AlgorithmWithGod/JHLEE325

[20260315] BOJ / G2 / 공항 / 이준희

Author: ShinHeeEul

JHLEE325/202603/15 BOJ G2 공항.md

@@ -0,0 +1,47 @@
+```java
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    static int[] parent;
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        int G = Integer.parseInt(br.readLine());
+        int P = Integer.parseInt(br.readLine());
+
+        parent = new int[G + 1];
+        for (int i = 1; i <= G; i++) {
+            parent[i] = i;
+        }
+
+        int count = 0;
+        for (int i = 0; i < P; i++) {
+            int gi = Integer.parseInt(br.readLine());
+
+            int availableGate = find(gi);
+
+            if (availableGate == 0) break;
+
+            count++;
+            
+            union(availableGate, availableGate - 1);
+        }
+
+        System.out.println(count);
+    }
+
+    static int find(int x) {
+        if (parent[x] == x) return x;
+        return parent[x] = find(parent[x]);
+    }
+
+    static void union(int x, int y) {
+        x = find(x);
+        y = find(y);
+        if (x != y) {
+            parent[x] = y;
+        }
+    }
+}
+```