检测一个字符串是否有唯一的字符:比较我的解决方案“破解编码面试?”

I am working through the book "Cracking the Coding Interview" and I have come across questions here asking for answers, but I need help comparing my answer to the solution. My algorithm works, but I am having difficulty understand the solution in the book. Mainly because I don't understand what some of the operators are really doing. I am working through the book "Cracking the Cod