题解 | #对称的二叉树#

/*
 * function TreeNode(x) {
 *   this.val = x;
 *   this.left = null;
 *   this.right = null;
 * }
 */
/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 *
 * @param pRoot TreeNode类
 * @return bool布尔型
 */
function compare(a, b) {
    if (a === null && b === null) return true;
    if (a === null || b === null) return false;
    if (a.val!==b.val) return false;
    return compare(a.left,b.right)&&compare(a.right,b.left)
}

function isSymmetrical(pRoot) {
    if (pRoot === null) return true;
    return compare(pRoot.left,pRoot.right)
}
module.exports = {
    isSymmetrical: isSymmetrical,
};