⭐️⭐️⭐️ # 題目敘述 You are given a string s , which contains stars * . In one operation, you can: Choose a star in s . Remove the closest non-star character to its left, as well as remove the star itself. Return the string after all stars have been removed. Note: The input will be generated such that...

⭐️ # 題目敘述 Given a string s containing just the characters '(' , ')' , '{' , '}' , '[' and ']' , determine if the input string is valid. An input string is valid if: Open brackets must be closed by the same type of brackets. Open...

⭐️⭐️⭐️⭐️⭐️ # 題目敘述 There is a directed graph of n colored nodes and m edges. The nodes are numbered from 0 to n - 1 . You are given a string colors where colors[i] is a lowercase English letter representing the color of the ith node in this graph (0-indexed). You are also given a 2D array edges where...

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⭐️⭐️⭐️ # 題目敘述 Given a reference of a node in a connected undirected graph. Return a deep copy (clone) of the graph. Each node in the graph contains a value ( int ) and a list ( List[Node] ) of its neighbors. class Node { public int val; public List<Node>...

⭐️⭐️⭐️⭐️ # Uber: The World's Modern Taxi A new taxi trend is taking over the world. Uber doesn't have a long history, but it has proven it's here to stay by providing major benefits and a competitive spirit. Travis Kalanick and Garrett Camp launched the Uber transportation app in 2009 in...

⭐️⭐️⭐️ # 題目敘述 You are given an m x n binary matrix grid , where 0 represents a sea cell and 1 represents a land cell. A move consists of walking from one land cell to another adjacent (4-directionally) land cell or walking off the boundary of the grid . Return the number of land cells in grid for...

⭐️⭐️⭐️ # 題目敘述 Given a 2D grid consists of 0s (land) and 1s (water). An island is a maximal 4-directionally connected group of 0s and a closed island is an island totally (all left, top, right, bottom) surrounded by 1s . Return the number of closed islands. # Example 1: Input: grid =...

⭐️⭐️⭐️ # 題目敘述 You are given a 0-indexed array nums comprising of n non-negative integers. In one operation, you must: Choose an integer i such that 1 <= i < n and nums[i] > 0 . Decrease nums[i] by 1. Increase nums[i - 1] by 1. Return the minimum possible value of the maximum...

⭐️⭐️⭐️ # 題目敘述 Given a string s , partition the string into one or more substrings such that the characters in each substring are unique. That is, no letter appears in a single substring more than once. Return the minimum number of substrings in such a partition. Note that each character should...