404. Sum of Left Leaves

leetcode/0404.Sum-of-Left-Leaves/README.md

1.7.1465 B

题目

Find the sum of all left leaves in a given binary tree.

Example:

    3
   / \
  9  20
    /  \
   15   7

There are two left leaves in the binary tree, with values 9 and 15 respectively. Return 24.

计算给定二叉树的所有左叶子之和。