1161 最大层内元素和

code

/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} root
 * @return {number}
 */
var maxLevelSum = function(root) {
    let result = [];
    function traverse(root, floor){
        if(root === null){
            return; 
        }
        if(result[floor] === undefined){
            result[floor] = root.val;
        } else {
            result[floor] = result[floor] + root.val;
        }
        traverse(root.left, floor + 1);
        traverse(root.right, floor + 1);
    };
    traverse(root, 0);
    return result.indexOf(Math.max(...result)) + 1;
};

总结

1. 都是层序遍历的变体...没啥特殊的