摘要：
X is a good number if after rotating each digit individually by 180 degrees, we get a valid number that is different from X. Each digit must be rotate 阅读全文
摘要：
Special binary strings are binary strings with the following two properties: The number of 0's is equal to the number of 1's. Every prefix of the bina 阅读全文
摘要：
You are given a string expression representing a Lisp-like expression to return the integer value of. The syntax for these expressions is given as fol 阅读全文