去年就在某牛人的博客上见到了，现在准备去玩玩。做题的方式跟Topcoder类似，刚刚去水了一题"Valid Palindrome"

 

1 class Solution { 2 public: 3     bool isPalindrome(string s) { 4         // Start typing your C/C++ solution below 5         // DO NOT write int main() function 6         string alnumstr; 7         transform(s.begin(), s.end(), s.begin(), [](char& ch){ return ::toupper(ch);}); 8         copy_if(s.begin(), s.end(), back_inserter(alnumstr), [](char& ch){ return ::isalnum(ch);}); 9         10         string another;11         reverse_copy(alnumstr.begin(), alnumstr.end(), back_inserter(another));12         13         return another == alnumstr;14         15     }16 };

 

1 class Solution { 2 public: 3     bool isPalindrome(string s) { 4         // Start typing your C/C++ solution below 5         // DO NOT write int main() function 6  7         const char* str = s.c_str(); 8         for (int i = 0, j = strlen(str); i < j; ) 9         {10             if (isalnum(str[i]) && isalnum(str[j]))11             {12                 if (toupper(str[i]) != toupper(str[j]))13                 {14                     return false;15                 }16                 else17                 {18                     ++i;19                     --j;20                 }21             }22             if (!isalnum(str[i])) ++i;23             if (!isalnum(str[j])) --j;24         }25         return true;26         27     }28 };