Arrays and strings in JavaScript

Problems to practice

• Two Sum
• Move Zeroes
• Best Time to Buy and Sell Stock
• Maximum Subarray
• Product of Array Except Self
• Valid Palindrome
• Longest Substring Without Repeating Characters
• Group Anagrams

Example: two sum

function twoSum(nums, target) {
  const map = new Map();

  for (let i = 0; i < nums.length; i++) {
    const needed = target - nums[i];
    if (map.has(needed)) return [map.get(needed), i];
    map.set(nums[i], i);
  }

  return [];
}

Time and space complexity

• Time: O(n)
• Space: O(n)