Problem Statement Description Given a string s, find the length of the longest substring without repeating characters. Examples Example 1: Input: s = "abcabcbb" Output: 3 Explanation: The answer is "abc", with the length of 3. Example 2: Input: s = "bbbbb" Output: 1 Explanation: The answer is "b", with the length of 1. Example 3: Input: s = "pwwkew" Output: 3 Explanation: The answer is "wke", with the length of 3....
Problem Statement Description Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct. Examples Example 1: Input: nums = [1,2,3,1] Output: true Example 2: Input: nums = [1,2,3,4] Output: false Example 3: Input: nums = [1,1,1,3,3,4,3,2,4,2] Output: true Constraints 1 <= nums.length <= 105 -109 <= nums[i] <= 109 Key Insights This is a very simple problem that introduces the concept of a hash set....
Problem Statement Description Given an array nums of size n, return the majority element. The majority element is the element that appears more than ⌊n / 2⌋ times. You may assume that the majority element always exists in the array. Examples Example 1: Input: nums = [3,2,3] Output: 3 Example 2: Input: nums = [2,2,1,1,1,2,2] Output: 2 Constraints n == nums.length 1 <= n <= 5 * 104 -109 <= nums[i] <= 109 Key Insights There are many different ways to solve this problem....