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### by Sumit Chourasia | Oct 06, 2020 | Category :coding | Tags : algorithmbinary-treedata-structureeasyleetcodetree #### Path Sum - Tree - Easy - LeetCode

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.

Note: A leaf is a node with no children.

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 path 5->4->11->2 which sum is 22.

``````/**
* Definition for a binary tree node.
* public class TreeNode {
*     public int val;
*     public TreeNode left;
*     public TreeNode right;
*     public TreeNode(int val=0, TreeNode left=null, TreeNode right=null) {
*         this.val = val;
*         this.left = left;
*         this.right = right;
*     }
* }
*/
public class Solution {
public bool HasPathSum(TreeNode root, int sum) {
if(root == null){
return false;
}

if(root.left == null && root.right == null){
return root.val==sum;
}

return HasPathSum(root.left, sum-root.val)||HasPathSum(root.right,sum-root.val);
}
}``````

Time Complexity: O(n)

Space Complexity: O(1)