# LeetCode 15. 3Sum

Description https://leetcode.com/problems/3sum/description/ Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the…

# LeetCode 5. Longest Palindromic Substring

Description https://leetcode.com/problems/longest-palindromic-substring/description/ Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000.…

# LeetCode 20. Valid Parentheses

Description https://leetcode.com/problems/valid-parentheses/ Given a string containing just the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[‘ and ‘]’, determine if the input…

# LeetCode 8. String to Integer (atoi)

Description https://leetcode.com/problems/string-to-integer-atoi/ Implement atoi to convert a string to an integer. Hint: Carefully consider all possible input cases. If you…

# LeetCode 4. Median of Two Sorted Arrays

Description https://leetcode.com/problems/median-of-two-sorted-arrays/ There are two sorted arrays nums1 and nums2 of size m and n respectively. Find the median of…