_951.java

package com.fishercoder.solutions;

import com.fishercoder.common.classes.TreeNode;

/**
 * 951. Flip Equivalent Binary Trees
 *
 * For a binary tree T, we can define a flip operation as follows: choose any node, and swap the left and right child subtrees.
 *
 * A binary tree X is flip equivalent to a binary tree Y if and only if we can make X equal to Y after some number of flip operations.
 *
 * Write a function that determines whether two binary trees are flip equivalent.  The trees are given by root nodes root1 and root2.
 *
 * Note:
 *  * Each tree will have at most 100 nodes.
 *  * Each value in each tree will be a unique integer in the range [0, 99].
 */

public class _951 {
    public static class Solution1 {
        public boolean flipEquiv(TreeNode root1, TreeNode root2) {
            if (root1 == null && root2 == null) {
                return true;
            }
            if (root1 == null || root2 == null) {
                return false;
            }

            if (root1.val != root2.val) {
                return false;
            }

            return (
                (flipEquiv(root1.left, root2.left) && flipEquiv(root1.right, root2.right))
                || (flipEquiv(root1.left, root2.right) && flipEquiv(root1.right, root2.left))
            );
        }
    }
}