LeetCode题解：0112（路径总和）
题目链接（简单）
| 解法 | 执行用时 |
|---|---|
| Ans 1 (Python) | 48ms (>91.80%) |
| Ans 2 (Python) | 64ms (>26.56%) |
解法一（广度优先迭代）：
def hasPathSum(self, root: TreeNode, sum: int) -> bool:
if root is None:
return False
node_dict = {root: root.val}
while len(node_dict) > 0:
temp_node_dict = {}
for node in node_dict:
node_value = node_dict[node]
if node.left is None and node.right is None:
if node_value == sum:
return True
if node.left is not None:
temp_node_dict[node.left] = node_value + node.left.val
if node.right is not None:
temp_node_dict[node.right] = node_value + node.right.val
node_dict = temp_node_dict
return False
解法二（递归）：
def hasPathSum(self, root: TreeNode, sum: int) -> bool:
if root is None:
return False
def helper(node, value):
if node.left is None and node.right is None:
return value == sum
if node.left is None:
return helper(node.right, value + node.right.val)
if node.right is None:
return helper(node.left, value + node.left.val)
return helper(node.right, value + node.right.val) or helper(node.left, value + node.left.val)
return helper(root, root.val)
