Algo:: Tree Sum Should Match the Target

LeetCode 112. Path Sum easy problem .

Question

• Given the root of a binary tree and an integer targetSum, return true if the tree has a root-to-leaf path such that adding up all the values along the path equals targetSum.
• A leaf is a node with no children.

Solution

var hasPathSum = function(root, targetSum) {

    let sum = 0;

    const helper = (root) => {
        if (root === null) {
            return;
        }

        sum += root.val;

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

        if (helper(root.left)){
            return true;
        }
        if (helper(root.right)) {
            return true;
        };
        sum -= root.val;
    }

    return helper(root) ? true : false;
};

If it is not clear please check my other Article on Tree Algorithm then it will be very much easier to understand.

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Reference:-

1. https://leetcode.com/problems/path-sum/?envType=study-plan-v2&envId=top-interview-150