Merge pull request #2343 from juhui-jeong/main

[juhui-jeong] WEEK 15 solutions

Author: TonyKim9401

subtree-of-another-tree/juhui-jeong.java

@@ -0,0 +1,28 @@
+class Solution {
+    public boolean isSubtree(TreeNode root, TreeNode subRoot) {
+        if(subRoot == null) return true;
+        if(root == null) return false;
+
+        Queue<TreeNode> queue = new LinkedList();
+        queue.offer(root);
+
+        while(!queue.isEmpty()) {
+            TreeNode cur = queue.poll();
+
+            if (cur.val == subRoot.val && isSame(cur, subRoot)) {
+                return true;
+            }
+
+            if (cur.left != null) queue.offer(cur.left);
+            if (cur.right != null) queue.offer(cur.right);
+        }
+        return false;
+    }
+
+    private boolean isSame(TreeNode a, TreeNode b) {
+        if (a == null && b == null) return true;
+        if (a == null || b == null) return false;
+        if (a.val != b.val) return false;
+        return isSame(a.left, b.left) && isSame(a.right, b.right);
+    }
+}