1161. Maximum Level Sum of a Binary Tree LeetCode Solution

In this guide, you will get 1161. Maximum Level Sum of a Binary Tree LeetCode Solution with the best time and space complexity. The solution to Maximum Level Sum of a Binary Tree problem is provided in various programming languages like C++, Java, and Python. This will be helpful for you if you are preparing for placements, hackathons, interviews, or practice purposes. The solutions provided here are very easy to follow and include detailed explanations.

Problem Statement
Complexity Analysis
Maximum Level Sum of a Binary Tree solution in C++
Maximum Level Sum of a Binary Tree solution in Java
Maximum Level Sum of a Binary Tree solution in Python
Additional Resources

1161. Maximum Level Sum of a Binary Tree LeetCode Solution image

Problem Statement of Maximum Level Sum of a Binary Tree

Given the root of a binary tree, the level of its root is 1, the level of its children is 2, and so on.
Return the smallest level x such that the sum of all the values of nodes at level x is maximal.

Example 1:

Input: root = [1,7,0,7,-8,null,null]
Output: 2
Explanation:
Level 1 sum = 1.
Level 2 sum = 7 + 0 = 7.
Level 3 sum = 7 + -8 = -1.
So we return the level with the maximum sum which is level 2.

Example 2:

Input: root = [989,null,10250,98693,-89388,null,null,null,-32127]
Output: 2

Constraints:

The number of nodes in the tree is in the range [1, 104].
-105 <= Node.val <= 105

Complexity Analysis

Time Complexity: O(n)
Space Complexity: O(n)

1161. Maximum Level Sum of a Binary Tree LeetCode Solution in C++

class Solution {
 public:
  int maxLevelSum(TreeNode* root) {
    int ans = 0;
    int maxLevelSum = INT_MIN;
    queue<TreeNode*> q{{root}};

    for (int level = 1; !q.empty(); ++level) {
      int levelSum = 0;
      for (int sz = q.size(); sz > 0; --sz) {
        TreeNode* node = q.front();
        q.pop();
        levelSum += node->val;
        if (node->left != nullptr)
          q.push(node->left);
        if (node->right != nullptr)
          q.push(node->right);
      }
      if (levelSum > maxLevelSum) {
        maxLevelSum = levelSum;
        ans = level;
      }
    }

    return ans;
  }
};
/* code provided by PROGIEZ */

1161. Maximum Level Sum of a Binary Tree LeetCode Solution in Java

class Solution {
  public int maxLevelSum(TreeNode root) {
    int ans = 0;
    int maxLevelSum = Integer.MIN_VALUE;
    Queue<TreeNode> q = new LinkedList<>(Arrays.asList(root));

    for (int level = 1; !q.isEmpty(); ++level) {
      int levelSum = 0;
      for (int sz = q.size(); sz > 0; --sz) {
        TreeNode node = q.poll();
        levelSum += node.val;
        if (node.left != null)
          q.offer(node.left);
        if (node.right != null)
          q.offer(node.right);
      }
      if (levelSum > maxLevelSum) {
        maxLevelSum = levelSum;
        ans = level;
      }
    }

    return ans;
  }
}
// code provided by PROGIEZ

1161. Maximum Level Sum of a Binary Tree LeetCode Solution in Python

class Solution:
  def maxLevelSum(self, root: TreeNode | None) -> int:
    ans = 0
    maxLevelSum = -math.inf
    q = collections.deque([root])

    level = 1
    while q:
      levelSum = 0
      for _ in range(len(q)):
        node = q.popleft()
        levelSum += node.val
        if node.left:
          q.append(node.left)
        if node.right:
          q.append(node.right)
      if levelSum > maxLevelSum:
        maxLevelSum = levelSum
        ans = level
      level += 1

    return ans
 # code by PROGIEZ