# 64. Minimum Path Sum

Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path. Note: You can only ...

# 152. Maximum Product Subarray

Find the contiguous subarray within an array (containing at least one number) which has the largest product. For example, given the array [2,3,-2,4], the contiguous subarray [2,3] has the largest ...

# 322. Coin Change

You are given coins of different denominations and a total amount of money amount. Write a function to compute the fewest number of coins that you need to make up that amount. If that amount of money ...

# Best Time to Buy and Sell Stock I,II,III

Best Time to Buy and Sell Stock I Say you have an array for which the ith element is the price of a given stock on day i. If you were only permitted to complete at...

# 279. Perfect Squares

Given a positive integer n, find the least number of perfect square numbers (for example, `1, 4, 9, 16, ...`) which sum to n. For example, given n = `12`,...

# 84. Largest Rectangle in Histogram

Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram. Above is a histogram where width ...

# 150. Evaluate Reverse Polish Notation

Evaluate the value of an arithmetic expression in Reverse Polish Notation. Valid operators are + , - , * and /. Each operand may be an integer or another expression. Some examples: ...

# 224. Basic Calculator

Implement a basic calculator to evaluate a simple expression string. The expression string may contain open `(` and closing parentheses `)`, the plus `+` or minus s...

# 134. Gas Station

Question: There are N gas stations along a circular route, where the amount of gas at station i is `gas[i]`. You have a car with an unlimited gas tank and it costs

# 42. Trapping Rain Water

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining. For example, Given [0,1,0,2,1,0,1,3,2,...