摘要：
Given an array of characters chars, compress it using the following algorithm: Begin with an empty string s. For each group of consecutive repeating c 阅读全文
摘要：
Case 1: 在一个sorted array里面找出target value的 index，如果target value 出现了多次，返回任何一个就可以了。 Cas 2: Find the smallest number which is greater than the target Case 阅读全文
摘要：
(This problem is an interactive problem.) A row-sorted binary matrix means that all elements are 0 or 1 and each row of the matrix is sorted in non-de 阅读全文
摘要：
给一个phone pad mapping like: {1，{‘A’,'B' , 'C'}}, {2, { 'D' , 'E' , 'F' }} ... {0， {'X', 'Y', 'Z'}}. 按一次1 返回A，连续两次返回B， 连续四次重新返回A. 输入一组数字，不清楚之间间隔，返回所有可能的 阅读全文
摘要：
Given an array of integers nums and an integer target. Return the number of non-empty subsequences of nums such that the sum of the minimum and maximu 阅读全文
摘要：
Given the root of a Binary Search Tree and a target number k, return true if there exist two elements in the BST such that their sum is equal to the g 阅读全文
摘要：
Given two strings s1 and s2, write a function to return true if s2 contains the permutation of s1. In other words, one of the first string's permutati 阅读全文
摘要：
Given a directed acyclic graph (DAG) of n nodes labeled from 0 to n - 1, find all possible paths from node 0 to node n - 1, and return them in any ord 阅读全文
摘要：
Given an array of positive integers arr (not necessarily distinct), return the lexicographically largest permutation that is smaller than arr, that ca 阅读全文
摘要：
You are given some lists of regions where the first region of each list includes all other regions in that list. Naturally, if a region X contains ano 阅读全文