Merge pull request #504 from AlgorithmWithGod/Seol-JY

[20250719] BOJ / G4 / 여행 가자 / 설진영

Author: ShinHeeEul

Seol-JY/202507/19 G4 여행 가자.md

@@ -0,0 +1,58 @@
+```java
+import java.util.*;
+
+public class Main {
+    static int[] parent;
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        int N = sc.nextInt();
+        int M = sc.nextInt();
+        
+        parent = new int[N + 1];
+        for (int i = 1; i <= N; i++) {
+            parent[i] = i;
+        }
+        for (int i = 1; i <= N; i++) {
+            for (int j = 1; j <= N; j++) {
+                int connected = sc.nextInt();
+                if (connected == 1) {
+                    union(i, j);
+                }
+            }
+        }
+
+        int[] plan = new int[M];
+        for (int i = 0; i < M; i++) {
+            plan[i] = sc.nextInt();
+        }
+
+        int root = find(plan[0]);
+        boolean possible = true;
+        for (int i = 1; i < M; i++) {
+            if (find(plan[i]) != root) {
+                possible = false;
+                break;
+            }
+        }
+
+        System.out.println(possible ? "YES" : "NO");
+    }
+
+    static int find(int x) {
+        if (x != parent[x]) {
+            parent[x] = find(parent[x]);
+        }
+        return parent[x];
+    }
+
+    static void union(int a, int b) {
+        int rootA = find(a);
+        int rootB = find(b);
+        if (rootA != rootB) {
+            parent[rootB] = rootA;
+        }
+    }
+}
+
+```