二叉树的右视图

[pwstrick]

199. 二叉树的右视图

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} root
 * @return {number[]}
 */
var rightSideView = function(root) {
    if(!root)
        return [];
    const queue = [root],
        nodes = [];
    while(queue.length > 0) {
        let len = queue.length;
        nodes.push(queue[len-1].val);
        for(let i=0; i<len; i++) {
            queue[i].left && queue.push(queue[i].left);
            queue[i].right && queue.push(queue[i].right);
        }
        queue.splice(0, len);
    }
    return nodes;
};