Question_101.md

LeetCode Records - Question 101 Symmetric Tree

Attempt 1: Check left.left and right.right at the same time

class Solution {
    public boolean isSymmetric(TreeNode root) {
        if (root == null) {
            return true;
        }

        return isSymmetricRecursion(root.left, root.right);
    }

    boolean isSymmetricRecursion(TreeNode left, TreeNode right) {
        if (left == null && right == null) {
            return true;
        } else if (left == null || right == null) {
            return false;
        }

        if (left.val != right.val) {
            return false;
        }

        if (!isSymmetricRecursion(left.left, right.right)) {
            return false;
        }
        if (!isSymmetricRecursion(left.right, right.left)) {
            return false;
        }

        return true;
    }
}

• Runtime: 0 ms (Beats: 100.00%)
• Memory: 42.02 MB (Beats: 12.59%)