LouisTsang-jk.github.io

合并二叉树

出处

合并二叉树｜leetcode

难度: 简单

题解/思路

递归

• 空间复杂度 O(min(m,n))

• 时间复杂度 O(min(m,n))

  /**
  * 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} root1
  * @param {TreeNode} root2
  * @return {TreeNode}
  */
  var mergeTrees = function (root1, root2) {
    if (!root1) return root2;
    if (!root2) return root1;
    root1.val += root2.val;
    root1.left = mergeTrees(root1.left, root2.left);
    root1.right = mergeTrees(root1.right, root2.right);
    return root1
  };