1448-Count-Good-Nodes-in-Binary-Tree.js

/**
 * https://leetcode.com/problems/count-good-nodes-in-binary-tree/
 * Time O(N) | Space O(H)
 * @param {TreeNode} root
 * @return {number}
 */
 var goodNodes = function(root, max = -Infinity, total = [ 0 ]) {
    count(root, max, total);

    return total[0]
};

const count = (root, max, total) => {
    const isBaseCase = root === null;
    if (isBaseCase) return 0;

    return dfs(root, max, total);
}

const dfs = (root, max, total) => {
    const isGood = max <= root.val
    if (isGood) total[0]++;

    max = Math.max(max, root.val);

    count(root.left, max, total);
    count(root.right, max, total);
}

/**
 * https://leetcode.com/problems/count-good-nodes-in-binary-tree/
 * Time O(N) | Space O(W)
 * @param {TreeNode} root
 * @return {number}
 */
var goodNodes = function(root, ) {
    const isBaseCase = root === null;
    if (isBaseCase) return 0
    
    return bfs([[ root, -Infinity ]]);
}

const bfs = (queue, total = 0) => {
    while (queue.length) {
        for (let i = (queue.length - 1); 0 <= i; i--) {
            let [ root, max ] = queue.shift();

            const isGood = max <= root.val;
            if (isGood) total++;

            max = Math.max(max, root.val);

            if (root.right) queue.push([ root.right, max ]);
            if (root.left) queue.push([ root.left, max ]);
        }
    }

    return total;
}