Lstmxx的空间

513. 找树左下角的值

给定一个二叉树，在树的最后一行找到最左边的值。

链接

/**
 * Definition for a binary tree node.
 * class TreeNode {
 *     val: number
 *     left: TreeNode | null
 *     right: TreeNode | null
 *     constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
 *         this.val = (val===undefined ? 0 : val)
 *         this.left = (left===undefined ? null : left)
 *         this.right = (right===undefined ? null : right)
 *     }
 * }
 */

function findBottomLeftValue(root: TreeNode | null): number {
  const nodeQues: TreeNode[] = [root]
  let res = 0
  while(nodeQues.length > 0) {
    const nodes = nodeQues.splice(0)
    const len = nodes.length
    for(let i = 0; i < len; i++) {
      const node = nodes[i]
      if (node) {
        if (node.left) {
          nodeQues.push(node.left)
        }
        if (node.right) {
          nodeQues.push(node.right)
        }
      }
    }
    if (nodeQues.length === 0) {
      res = nodes[0].val
    }
  }
  return res
};