[Leetcode] path sum

Question

Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.

For example:
Given the below binary tree and sum = 22,

              5             /             4   8           /   /           11  13  4         /  \              7    2      1

Return true, as there exist a root-to-leaf path5->4->11->2Which sum is 22.

Answer

Recursive Solutions

/*** Definition for binary tree * Public class treenode {* int val; * treenode left; * treenode right; * treenode (int x) {val = x ;} *} */public class solution {public Boolean haspathsum (treenode root, int sum) {If (root = NULL) {return false;} If (root. left = NULL & root. right = NULL & sum-root.val = 0) {// note that there must be a path from the root node to the leaf node at the same time, only the root node is not the required return true ;} boolean BL = false; Boolean BR = false; If (root. left ! = NULL) {BL = haspathsum (root. Left, sum-root.val);} If (root. Right! = NULL) {BR = haspathsum (root. Right, sum-root.val);} return BL | BR ;}}

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