JS-PROBLEMS.md

PROBLEM SET

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Problem 1: Two Sum Sorted (Array)

Difficulty: Easy
Category: Array

Description: Given a sorted array of integers nums and an integer target, return the indices (1-based) of the two numbers such that they add up to target.

Constraints:

• 2 <= nums.length <= 10^4
• -10^9 <= nums[i] <= 10^9
• nums is sorted in non-decreasing order
• There is exactly one solution

Function Signature:

function twoSumSorted(nums, target) {
  // your code here
}

Example Tests:

twoSumSorted([2, 7, 11, 15], 9); // [1, 2]
twoSumSorted([1, 2, 3, 4, 6], 6); // [2, 4]
twoSumSorted([-3, 0, 2, 4, 10], 7); // [3, 5]

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Problem 2: Max Consecutive Ones (Array)

Difficulty: Easy
Category: Array

Description: Given a binary array nums, return the maximum number of consecutive 1's in the array.

Constraints:

• 1 <= nums.length <= 10^5
• nums[i] is either 0 or 1

Function Signature:

function findMaxConsecutiveOnes(nums) {
  // your code here
}

Example Tests:

findMaxConsecutiveOnes([1,1,0,1,1,1]); // 3
findMaxConsecutiveOnes([1,0,1,1,0,1]); // 2
findMaxConsecutiveOnes([0,0,0]); // 0

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Problem 3: First Unique Character (Hash Table)

Difficulty: Easy
Category: Hash Table

Description: Given a string s, find the first non-repeating character and return its index. If it does not exist, return -1.

Constraints:

• 1 <= s.length <= 10^5
• s consists of only lowercase English letters

Function Signature:

function firstUniqChar(s) {
  // your code here
}

Example Tests:

firstUniqChar("leetcode"); // 0
firstUniqChar("loveleetcode"); // 2
firstUniqChar("aabb"); // -1

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Problem 4: Group Anagrams (Hash Table)

Difficulty: Medium
Category: Hash Table

Description: Given an array of strings strs, group the anagrams together. You can return the answer in any order.

Constraints:

• 1 <= strs.length <= 10^4
• 0 <= strs[i].length <= 100
• strs[i] consists of lowercase English letters

Function Signature:

function groupAnagrams(strs) {
  // your code here
}

Example Tests:

groupAnagrams(["eat", "tea", "tan", "ate", "nat", "bat"]);
// [["eat","tea","ate"],["tan","nat"],["bat"]]

groupAnagrams([""]);
// [[""]]

groupAnagrams(["a"]);
// [["a"]]

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Problem 5: Search in Rotated Sorted Array (Divide and Conquer)

Difficulty: Medium
Category: Divide and Conquer

Description: Suppose an array of length n sorted in ascending order is rotated between 1 and n times. Given the array nums and an integer target, return the index of target if it is in nums, or -1 if it is not.

Constraints:

• 1 <= nums.length <= 5000
• -10^4 <= nums[i] <= 10^4
• All values of nums are unique
• nums is rotated at some pivot

Function Signature:

function searchRotated(nums, target) {
  // your code here
}

Example Tests:

searchRotated([4,5,6,7,0,1,2], 0); // 4
searchRotated([4,5,6,7,0,1,2], 3); // -1
searchRotated([1], 0); // -1

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Problem 6: Merge K Sorted Arrays (Divide and Conquer)

Difficulty: Hard
Category: Divide and Conquer

Description: You are given an array of k sorted arrays, merge them into one sorted array.

Constraints:

• 1 <= k <= 100
• 0 <= arrays[i].length <= 1000
• -10^4 <= arrays[i][j] <= 10^4

Function Signature:

function mergeKSortedArrays(arrays) {
  // your code here
}

Example Tests:

mergeKSortedArrays([[1,4,5],[1,3,4],[2,6]]);
// [1,1,2,3,4,4,5,6]

mergeKSortedArrays([[]]);
// []

mergeKSortedArrays([[1], [0]]);
// [0,1]

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