[Leetcode] Path Sum

Path Sum

Given a binary tree and a sum, determine if the tree has a root-to-leaf path such this 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           /   /           /  4         /  \              7    2      1

Return true, as there exist a root-to-leaf path 5->4->11->2 which sum is 22.

Problem Solving Ideas:

Test instructions to determine whether there is a path from the root to the leaf and for the given path. Recursion can be. Note that if you give an empty tree and 0, you should return false.

/** * Definition for a binary tree node. * struct TreeNode {*     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode (int x): Val (x), left (NULL) , right (NULL) {}}; */class Solution {public:    bool Haspathsum (treenode* root, int sum) {        if (root==null) {            return false;        }        if (root->left==null&&root->right==null&&sum==root->val) {            return true;        }        if (root->left!=null) {            if (haspathsum (Root->left, Sum-root->val)) {                return true;            }        }        if (root->right!=null) {            if (haspathsum (Root->right, Sum-root->val)) {                return true;            }        }        return false;    }};

[Leetcode] Path Sum