index.js

// 101.js
// node index.js
// npm test
// warming up before your test

// challenge question:
// Given a binary tree represented as an array,
// write a function that calculates the sum of the left branch and the sum of the right branch, and returns the largest branch as a string.
// If the left branch is larger, return 'Left'
// If the right branch is larger, return 'Right'
// If they are equal, return 0
// If the tree has 0 nodes, return 0
// -1 is a non-existent node

let arr = [3, 6, 2, 9, -1, 10]; // Left
// let arr = [1, 4, 100, 5]; // Right
// let arr = [1, 10, 5, 1, 12, 6]; // Equal
// let arr = []; // Empty tree
// let arr = [7]; // Only root node

const solution = (arr) => {
    // Type your solution here

    console.log(arr);

    function filterArr(arr) {
        // Remove root node
        arr.shift();
        // Remove all non-existent nodes (-1)
        return arr.filter((node) => node !== -1);
    }

    function leftBranchSum(arr) {
        let sum = 0;
        for (let i = 0; i < arr.length; i += 2) {
            sum += arr[i];
        }
        return sum;
    }

    function rightBranchSum(arr) {
        let sum = 0;
        for (let i = 1; i < arr.length; i += 2) {
            sum += arr[i];
        }
        return sum;
    }

    // filterArr(arr);
    arr = filterArr(arr);

    console.log("Filtered Array: ", arr);

    let leftSum = leftBranchSum(arr);
    let rightSum = rightBranchSum(arr);

    console.log("Left Branch Sum", leftSum);
    console.log("Right Branch Sum", rightSum);

    function calcLrgstBranch(arr, leftSum, rightSum) {
        let res = null;
        if (leftSum > rightSum) {
            res = "Left";
        } else if (leftSum < rightSum) {
            res = "Right";
        } else if (leftSum === rightSum && arr.length > 1) {
            res = "Equal";
        } else if (arr.length == 0 || arr.length == 1) {
            res = 0;
        }
        return res;
    }

    let result = calcLrgstBranch(arr, leftSum, rightSum);
    console.log("Result:", result);

    return result;
};

solution(arr);

module.exports = solution;