Find the Distance Between Two Nodes in the Binary Tree using JavaScript

class TreeNode {
    constructor(val = 0, left = null, right = null) {
        this.val = val;
        this.left = left;
        this.right = right;
    }
}

// Helper function to find
// the LCA of two nodes
function findLCA(root, n1, n2) {
    if (root === null) {
        return null;
    }

    if (root.val === n1 || root.val === n2) {
        return root;
    }

    const leftLCA = findLCA(root.left, n1, n2);
    const rightLCA = findLCA(root.right, n1, n2);

    if (leftLCA !== null && rightLCA !== null) {
        return root;
    }

    return (leftLCA !== null) ? leftLCA : rightLCA;
}

// Helper function to find the 
// distance from the LCA to a given node
function findDistanceFromLCA(lca, k, dist) {
    if (lca === null) {
        return -1;
    }

    if (lca.val === k) {
        return dist;
    }

    const leftDist = findDistanceFromLCA(lca.left, k, dist + 1);
    if (leftDist !== -1) {
        return leftDist;
    }

    return findDistanceFromLCA(lca.right, k, dist + 1);
}

// Main function to find the
// distance between two nodes
function findDistance(root, n1, n2) {
    const lca = findLCA(root, n1, n2);

    const d1 = findDistanceFromLCA(lca, n1, 0);
    const d2 = findDistanceFromLCA(lca, n2, 0);

    return d1 + d2;
}

// Example usage
const root = new TreeNode(12);
root.left = new TreeNode(22);
root.right = new TreeNode(32);
root.left.left = new TreeNode(42);
root.left.right = new TreeNode(52);
root.right.left = new TreeNode(62);
root.right.right = new TreeNode(72);

const n1 = 42, n2 = 52;
console.log(`Distance between nodes ${n1} and 
                ${n2} is ${findDistance(root, n1, n2)}`);

class TreeNode {
    constructor(val = 0, left = null, right = null) {
        this.val = val;
        this.left = left;
        this.right = right;
    }
}

// Helper function to find the path 
// from the root to a given node
function findPath(root, path, k) {
    if (root === null) {
        return false;
    }

    // Append current node's value to the path
    path.push(root.val);

    // Check if the current node is the desired node
    if (root.val === k) {
        return true;
    }

    // Recursively check left and right subtrees
    if ((root.left && findPath(root.left, path, k))
        || (root.right && findPath(root.right, path, k))) {
        return true;
    }

    // If not found, remove 
    // current node's value from path
    path.pop();
    return false;
}

// Main function to find the distance between two nodes
function findDistancePathMethod(root, n1, n2) {
    if (root === null) {
        return 0;
    }

    const path1 = [];
    const path2 = [];

    // Find paths from root to n1 and n2
    if (!findPath(root, path1, n1) || !findPath(root, path2, n2)) {
        return -1;
    }

    // Find the longest common prefix
    let i = 0;
    while (i < path1.length && i < path2.length) {
        if (path1[i] !== path2[i]) {
            break;
        }
        i++;
    }

    // Calculate the distance
    return (path1.length + path2.length - 2 * i);
}

// Example usage
const root = new TreeNode(12);
root.left = new TreeNode(22);
root.right = new TreeNode(32);
root.left.left = new TreeNode(42);
root.left.right = new TreeNode(52);
root.right.left = new TreeNode(62);
root.right.right = new TreeNode(72);

const n1 = 42, n2 = 52;
console.log(`Distance between nodes ${n1} and
 ${n2} is ${findDistancePathMethod(root, n1, n2)}`);