[LeetCode] 227. Basic Calculator II
Implement a basic calculator to evaluate a simple expression string. The expression string contains only non-negative integers, +, -, *, / operators and empty spaces . The integer division should
[LeetCode] 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 sign -, non-negative integers and empty spa
[LeetCode] 981. Time Based Key-Value Store
Design a time-based key-value data structure that can store multiple values for the same key at different time stamps and retrieve the key’s value at a certain timestamp. Implement the TimeMap class:
[LeetCode] 85. Maximal Rectangle
Given a rows x cols binary matrix filled with 0’s and 1’s, find the largest rectangle containing only 1’s and return its area. Example 1:Input: matrix = [ [“1”,”0”,”1”,”0”,”0”], [“1”,”0”,”1
[LeetCode] 119. Pascal's Triangle II
Given an integer rowIndex, return the rowIndexth (0-indexed) row of the Pascal’s triangle. In Pascal’s triangle, each number is the sum of the two numbers directly above it as shown: Example 1:Input:
[LeetCode] 118. Pascal's Triangle
Given an integer numRows, return the first numRows of Pascal’s triangle. In Pascal’s triangle, each number is the sum of the two numbers directly above it as shown: Example 1:Input: numRows = 5Ou
[LeetCode] 402. Remove K Digits
Given string num representing a non-negative integer num, and an integer k, return the smallest possible integer after removing k digits from num. Example 1:Input: num = “1432219”, k = 3Outp
[LeetCode] 987. Vertical Order Traversal of a Binary Tree
Given the root of a binary tree, calculate the vertical order traversal of the binary tree. For each node at position (row, col), its left and right children will be at positions (row + 1, col - 1) an