摘要： Description:Count the number of prime numbers less than a non-negative number, n. 1 class Solution { 2 public: 3 int countPrimes(int n) { 4 ... 阅读全文

摘要： Given a string S and a string T, count the number of distinct subsequences of T in S.A subsequence of a string is a new string which is formed from th... 阅读全文

摘要： Given two words word1 and word2, find the minimum number of steps required to convert word1 to word2. (each operation is counted as 1 step.)You have t... 阅读全文