面试题 - 删重

// .假设有一个字符串aabcad，请写一段程序，去掉字符串中不相邻的重复字符串，既上述字符串处理之后的输出结果为：aabcd
        
        NSMutableString *str = [[NSMutableString alloc] initWithFormat: @"aabcad"];
        
        for (int i = 0; i < str.length - 1; i++) {
            unsigned char s = [str characterAtIndex:i];
            //从后面隔一个 开始
            for (int j = i + 2; j < str.length; j++) {
                if (s == [str characterAtIndex:j]) {
                    [str deleteCharactersInRange:NSMakeRange(j, 1)];
                }
            }
        }
         NSLog(@"删重后： %@",str);