# LeetCode 70. Climbing Stairs

Description https://leetcode.com/problems/climbing-stairs/ You are climbing a staircase. It takes n steps to reach the top. Each time you can either climb 1 or 2 steps. In…

# LeetCode 387. First Unique Character in a String

Description Given a string, find the first non-repeating character in it and return it’s index. If it doesn’t exist, return…

# LeetCode 84. Largest Rectangle in Histogram

Description https://leetcode.com/problems/largest-rectangle-in-histogram/ Given an array of integers heights representing the histogram’s bar height where the width of each bar is 1, return the area…

# LeetCode 139. Word Break

Description Given a non-empty string s and a dictionary wordDict containing a list of non-empty words, determine if s can be segmented into a space-separated sequence of one or more…

# LeetCode 42. Trapping Rain Water

Description https://leetcode.com/problems/trapping-rain-water/description/ Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water…

# LeetCode 155. Min Stack

Description Design a stack that supports push, pop, top, and retrieving the minimum element in constant time. push(x) — Push…

# LeetCode 20. Valid Parentheses

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

# 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…