摘要：
Given a string s representing a valid expression, implement a basic calculator to evaluate it, and return the result of the evaluation. Note: You are 阅读全文
摘要：
Given a string s which represents an expression, evaluate this expression and return its value. The integer division should truncate toward zero. You 阅读全文
摘要：
The complement of an integer is the integer you get when you flip all the 0's to 1's and all the 1's to 0's in its binary representation. For example, 阅读全文