[이진희] 2026/10/22

leetcode3/이진희/572. Subtree of Another Tree.java

@@ -0,0 +1,47 @@
+/* 
+
+1. 아이디어 : 먼저 subTree의 노드를 rootNode에서 찾은뒤, 완전탐색으로 같은지 체크
+
+2. 시간복잡도 : O(N)
+
+3. 자료구조/알고리즘 : 완전탐색
+
+ */
+
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode() {}
+ *     TreeNode(int val) { this.val = val; }
+ *     TreeNode(int val, TreeNode left, TreeNode right) {
+ *         this.val = val;
+ *         this.left = left;
+ *         this.right = right;
+ *     }
+ * }
+ */
+class Solution {
+
+    public boolean isSubtree(TreeNode root, TreeNode subRoot) {
+        return findPos(root, subRoot);
+    }
+
+    public boolean findPos(TreeNode root, TreeNode subRoot) {
+        if(root == null) return false;
+
+        if(checkSame(root, subRoot)) return true;
+
+        return findPos(root.left, subRoot) || findPos(root.right, subRoot);
+    }
+
+    public boolean checkSame(TreeNode root, TreeNode subRoot) {
+        if(root == null && subRoot == null) return true;
+
+        if(root == null || subRoot == null || root.val != subRoot.val) return false;
+
+        return checkSame(root.left, subRoot.left) && checkSame(root.right, subRoot.right);
+    }
+}