2022-10-04 Daily-Challenge

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In: DailyChallenge

Today I have done leetcode's October LeetCoding Challenge with cpp.

October LeetCoding Challenge 4

Description

Path Sum

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.

Example 1:

img

Input: root = [5,4,8,11,null,13,4,7,2,null,null,null,1], targetSum = 22
Output: true
Explanation: The root-to-leaf path with the target sum is shown.

Example 2:

img

Input: root = [1,2,3], targetSum = 5
Output: false
Explanation: There two root-to-leaf paths in the tree:
(1 --> 2): The sum is 3.
(1 --> 3): The sum is 4.
There is no root-to-leaf path with sum = 5.

Example 3:

Input: root = [], targetSum = 0
Output: false
Explanation: Since the tree is empty, there are no root-to-leaf paths.

Constraints:

  • The number of nodes in the tree is in the range [0, 5000].
  • -1000 <= Node.val <= 1000
  • -1000 <= targetSum <= 1000

Solution

class Solution {
public:
  bool hasPathSum(TreeNode* root, int sum) {
    if(!root) return false;
    if(root->left || root->right) return hasPathSum(root->left, sum-root->val) || hasPathSum(root->right, sum-root->val);
    return sum == root->val;
  }
};

// Accepted
// 117/117 cases passed (10 ms)
// Your runtime beats 90.94 % of cpp submissions
// Your memory usage beats 38.76 % of cpp submissions (21.4 MB)
Algorithm