0300-longest-increasing-subsequence.js

/**
 * DP - Bottom Up
 * Array - Tabulation
 * Time O(N^2) | Space O(N)
 * https://leetcode.com/problems/longest-increasing-subsequence/
 * @param {number[]} nums
 * @return {number}
 */
var lengthOfLIS = (nums) => {
    const tabu = initTabu(nums);/*               | Space O(N) */

    linearSearch(nums, tabu);   /* Time O(N * N) | Space O(N)*/

    return Math.max(...tabu);   /* Time O(N) */
};

const initTabu = (nums) => new Array(nums.length).fill(1);

var linearSearch = (nums, tabu) => {
    for (let right = 1; (right < nums.length); right++) {/* Time O(N) */
        for (let left = 0; (left < right); left++) {         /* Time O(N) */
            const canUpdate = nums[left] < nums[right];
            if (!canUpdate) continue;

            const [ _left, _right ] = [ (tabu[left] + 1), tabu[right] ];
            tabu[right] = Math.max(_right, _left);           /* Space O(N) */
        }
    }
}

/**
 * Array - Subsequence
 * Time O(N^2) | Space O(N)
 * https://leetcode.com/problems/longest-increasing-subsequence/
 * @param {number[]} nums
 * @return {number}
 */
var lengthOfLIS = (nums) => {
    const subsequence = linearSort(nums);/* Time O(N * N) | Space O(N) */

    return subsequence.length;
}

var linearSort = (nums, subsequence = []) => {
    for (const num of nums) {/* Time O(N) */
        const max = subsequence[subsequence.length - 1];

        const canAdd = max < num;
        if (canAdd) { subsequence.push(num); continue; }/* Space O(N) */

        const index = getMax(subsequence, num);         /* Time O(N) */

        subsequence[index] = num;
    }

    return subsequence;
}


const getMax = (subsequence, num, index = 0) => {
    const isLess = () => subsequence[index] < num;
    while (isLess()) index++;/* Time O(N) */

    return index;
}

/**
 * Array - Subsequence
 * Time O(N * log(N)) | Space O(N)
 * https://leetcode.com/problems/longest-increasing-subsequence/
 * @param {number[]} nums
 * @return {number}
 */
var lengthOfLIS = (nums) => {
    const subsequence = logarithmicSort(nums);/* Time O(N * log(N) */

    return subsequence.length;
}

var logarithmicSort = (nums, subsequence = []) => {
    for (const num of nums) {/* Time O(N) */
        const max = subsequence[(subsequence.length - 1)];

        const canAdd = (max < num);
        if (canAdd) { subsequence.push(num); continue; }/* Space O(N) */

        const index = binarySearch(num, subsequence);   /* Time O(log(N)) */

        subsequence[index] = num;
    }

    return subsequence;
}

const binarySearch = (num, subsequence) => {
    let [ left, right ] = [ 0, (subsequence.length - 1) ];

    while (left < right) {/* Time O(log(N)) */
        const mid = ((left + right) >> 1);
        const guess = subsequence[mid];

        const isNumTarget = (num === guess);
        if (isNumTarget) return mid;

        const isNumGreater = (guess < num);
        if (isNumGreater) left = (mid + 1);

        const isNumLess = (num < guess);
        if (isNumLess) right = mid;
    }

    return left;
}