path_sum.go

package main

// Definition for a binary tree node.
type TreeNode struct {
	Val   int
	Left  *TreeNode
	Right *TreeNode
}

// Runtime: 0 ms, faster than 100.00% of Go online submissions for Path Sum.
// Memory Usage: 4.6 MB, less than 94.24% of Go online submissions for Path Sum.
func hasPathSum(root *TreeNode, targetSum int) bool {
	if root == nil {
		return false
	}
	if root.Left == nil && root.Right == nil {
		return root.Val == targetSum
	}
	return hasPathSum(root.Left, targetSum-root.Val) ||
		hasPathSum(root.Right, targetSum-root.Val)
}