摘要：
Description:Implement strStr().Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.Code1:vector g... 阅读全文
摘要：
Description：Given an integer n, count the total number of digit 1 appearing in all non-negative integers less than or equal to n.For example:Given n =... 阅读全文