摘要：Given a string s consisting only of characters a, b and c. Return the number of substrings containing at least one occurrence of all these characters  阅读全文

摘要：There is a supermarket that is frequented by many customers. The products sold at the supermarket are represented as two parallel integer arrays produ 阅读全文

摘要：You are given an integer array arr. Sort the integers in the array in ascending order by the number of 1's in their binary representation and in case 阅读全文

摘要：You are given an array target of n integers. From a starting array arr consisting of n 1's, you may perform the following procedure : let x be the sum 阅读全文