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

December LeetCoding Challenge 7

Description

Range Sum of BST

Given the root node of a binary search tree and two integers low and high, return the sum of values of all nodes with a value in the inclusive range [low, high].

Example 1:

Input: root = [10,5,15,3,7,null,18], low = 7, high = 15
Output: 32
Explanation: Nodes 7, 10, and 15 are in the range [7, 15]. 7 + 10 + 15 = 32.

Example 2:

Input: root = [10,5,15,3,7,13,18,1,null,6], low = 6, high = 10
Output: 23
Explanation: Nodes 6, 7, and 10 are in the range [6, 10]. 6 + 7 + 10 = 23.

Constraints:

• The number of nodes in the tree is in the range [1, 2 * 104].
• 1 <= Node.val <= 105
• 1 <= low <= high <= 105
• All Node.val are unique.

Solution

auto speedup = [](){
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  return 0;
}();
class Solution {
public:
  int rangeSumBST(TreeNode* root, int low, int high) {
    if(!root) return 0;
    if(root->val > high) return rangeSumBST(root->left, low, high);
    if(root->val < low) return rangeSumBST(root->right, low, high);
    return root->val + rangeSumBST(root->left, low, high) + rangeSumBST(root->right, low, high);
  }
};

// Accepted
// 41/41 cases passed (92 ms)
// Your runtime beats 99.56 % of cpp submissions
// Your memory usage beats 60.14 % of cpp submissions (64.6 MB)