Here, We see Find Largest Value in Each Tree Row LeetCode Solution. This Leetcode problem is done in many programming languages like C++, Java, JavaScript, Python, etc. with different approaches.

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Find Largest Value in Each Tree Row LeetCode Solution

Problem Statement

Given the root of a binary tree, return an array of the largest value in each row of the tree (0-indexed).

Example 1:

Input: root = [1,3,2,5,3,null,9]
Output: [1,3,9]

Example 2:
Input: root = [1,2,3]
Output: [1,3]

Find Largest Value in Each Tree Row LeetCode Solution C++

class Solution {
public:
    vector<int> largestValues(TreeNode* root) {
        if (!root) return {};
        vector<int> result;
        queue<TreeNode*> queue;
        queue.push(root);
        while (!queue.empty()) {
            int curr_level_size = queue.size();
            int max_val = INT_MIN;
            for (int i = 0; i < curr_level_size; ++i) {
                TreeNode* node = queue.front();
                queue.pop();
                max_val = std::max(max_val, node->val);
                if (node->left) queue.push(node->left);
                if (node->right) queue.push(node->right);
            }
            result.push_back(max_val);
        }
        return result;        
    }
};Code language: PHP (php)

Find Largest Value in Each Tree Row Solution Java

class Solution {
    public List<Integer> largestValues(TreeNode root) {
        if (root == null) return new ArrayList<>();
        List<Integer> result = new ArrayList<>();
        Queue<TreeNode> queue = new LinkedList<>();
        queue.offer(root);
        while (!queue.isEmpty()) {
            int curr_level_size = queue.size();
            int max_val = Integer.MIN_VALUE;
            for (int i = 0; i < curr_level_size; i++) {
                TreeNode node = queue.poll();
                max_val = Math.max(max_val, node.val);
                if (node.left != null) queue.offer(node.left);
                if (node.right != null) queue.offer(node.right);
            }
            result.add(max_val);
        }
        return result;
    }
}Code language: PHP (php)

Find Largest Value in Each Tree Row Solution JavaScript

var largestValues = function(root) {
    if (!root) return [];
    const result = [];
    const queue = [root];
    while (queue.length) {
        let curr_level_size = queue.length;
        let max_val = Number.MIN_SAFE_INTEGER;
        for (let i = 0; i < curr_level_size; i++) {
            const node = queue.shift();
            max_val = Math.max(max_val, node.val);
            if (node.left) queue.push(node.left);
            if (node.right) queue.push(node.right);
        }
        result.push(max_val);
    }
    return result;    
};Code language: JavaScript (javascript)

Find Largest Value in Each Tree Row Solution Python

class Solution(object):
    def largestValues(self, root):
        if not root:
            return []
        result = []
        queue = deque([root])
        while queue:
            curr_level_size = len(queue)
            max_val = float('-inf')
            for _ in range(curr_level_size):
                node = queue.popleft()
                max_val = max(max_val, node.val)
                for child in [node.left, node.right]:
                    if child:
                        queue.append(child)
            result.append(max_val)
        return result