LeetCode lc112.路径总和

1. 题目地址：https://leetcode-cn.com/problems/path-sum/submissions/

2. 题目分析：【1】条件有两个：(1) 要求路径从根节点到叶子节点 (2) 要求值加和为 targetSum

【2】BFS 

var hasPathSum = function(root, targetSum) {
  if (!root) {
    return false;
  }
  let queen = [root];
  let node = null;
  while (queen.length) {
    let q_size = queen.length;
    while (q_size--) {
      node = queen.shift();
      if (node.left) {
        node.left.val += node.val;
        queen.push(node.left);
      }
      if (node.right) {
        node.right.val += node.val;
        queen.push(node.right);
      }
      if (node.val === targetSum && !node.left && !node.right) {
        return true;
      }
    }
  }
  return false;
};