* 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);
linearSearch(nums, tabu);
return Math.max(...tabu);
};
const initTabu = (nums) => new Array(nums.length).fill(1);
var linearSearch = (nums, tabu) => {
for (let right = 1; right < nums.length; right++) {
for (let left = 0; left < right; left++) {
const canUpdate = nums[left] < nums[right];
if (!canUpdate) continue;
const [_left, _right] = [tabu[left] + 1, tabu[right]];
tabu[right] = Math.max(_right, _left);
}
}
};
* 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);
return subsequence.length;
};
var linearSort = (nums, subsequence = []) => {
for (const num of nums) {
const max = subsequence[subsequence.length - 1];
const canAdd = max < num;
if (canAdd) {
subsequence.push(num);
continue;
}
const index = getMax(subsequence, num);
subsequence[index] = num;
}
return subsequence;
};
const getMax = (subsequence, num, index = 0) => {
const isLess = () => subsequence[index] < num;
while (isLess()) index++;
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);
return subsequence.length;
};
var logarithmicSort = (nums, subsequence = []) => {
for (const num of nums) {
const max = subsequence[subsequence.length - 1];
const canAdd = max < num;
if (canAdd) {
subsequence.push(num);
continue;
}
const index = binarySearch(num, subsequence);
subsequence[index] = num;
}
return subsequence;
};
const binarySearch = (num, subsequence) => {
let [left, right] = [0, subsequence.length - 1];
while (left < right) {
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;
};