Leetcode•Apr 06, 2026

Longest Increasing Subsequence

Hazrat Ali

Leetcode

Given an integer array nums, return the length of the longest strictly increasing .

 

Example 1:

Input: nums = [10,9,2,5,3,7,101,18]
Output: 4
Explanation: The longest increasing subsequence is [2,3,7,101], therefore the length is 4.

Example 2:

Input: nums = [0,1,0,3,2,3]
Output: 4

Example 3:

Input: nums = [7,7,7,7,7,7,7]
Output: 1

Solution
function lengthOfLIS(nums) {
    let tails = [];

    for (let num of nums) {
        let left = 0, right = tails.length;

        while (left < right) {
            let mid = Math.floor((left + right) / 2);
            if (tails[mid] < num) {
                left = mid + 1;
            } else {
                right = mid;
            }
        }

        tails[left] = num;
    }

    return tails.length;
}


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