/**
 * Brute Force - Linear Search
 * Time O(N^2) | Space O(1)
 * https://leetcode.com/problems/two-sum/
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = (nums, target) => {
    for (let curr = 0; curr < nums.length; curr++) {
        /* Time O(N) */
        const complement = target - nums[curr];

        for (let next = curr + 1; next < nums.length; next++) {
            /* Time O(N) */
            const num = nums[next];

            const isTarget = num === complement;
            if (isTarget) return [curr, next];
        }
    }

    return [-1, -1];
};

/**
 * Hash Map - 2 Pass
 * Time O(N) | Space O(N)
 * https://leetcode.com/problems/two-sum/
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = (nums, target) => {
    const map = getMap(nums); /* Time O(N) | Space O(N) */

    return getSum(nums, target, map); /* Time O(N) */
};

const getMap = (nums, map = new Map()) => {
    for (let index = 0; index < nums.length; index++) {
        /* Time O(N) */
        map.set(nums[index], index); /* Space O(N) */
    }

    return map;
};

const getSum = (nums, target, map) => {
    for (let index = 0; index < nums.length; index++) {
        /* Time O(N) */
        const complement = target - nums[index];
        const sumIndex = map.get(complement);

        const isTarget = map.has(complement) && map.get(complement) !== index;
        if (isTarget) return [index, sumIndex];
    }

    return [-1, -1];
};

/**
 * Hash Map - 1 Pass
 * Time O(N) | Space O(N)
 * https://leetcode.com/problems/two-sum/
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = (nums, target, map = new Map()) => {
    for (let index = 0; index < nums.length; index++) {
        /* Time O(N) */
        const num = nums[index];
        const complement = target - num;
        const sumIndex = map.get(complement);

        const isTarget = map.has(complement);
        if (isTarget) return [index, sumIndex];

        map.set(num, index); /* Space O(N) */
    }

    return [-1, -1];
};