[Leetcode] Valid palindrome

Valid palindrome

Topic:

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.

For example,
"A man, a plan, a canal: Panama"is a palindrome.
"race a car"is not a palindrome.

Note:
Are you consider that the string might is empty? This was a good question to ask during a interview.

For the purpose of this problem, we define empty string as valid palindrome.

C + + implementation:

#include <string> #include <iostream> #include <vector>using namespace Std;class solution {public:    bool Ispalindrome (string s) {        int length = S.length ();        if (length = = 0 | | length = = 1) return true;        int i = 0,j = length-1;        while (I <= j) {            char prev = s[i];            Char last = s[j];            BOOL p = isalpha (prev) | | IsDigit (prev);            bool L = isalpha (last) | | IsDigit (last);            if (P && l) {                if (tolower (prev) = = ToLower (last)) {                    ++i;                    --j;                    Continue;                } else{                    return false;                }            }            else if (p)--j;            else if (l) ++i;            else{--j;++i;}        }        return true;    }}; int main () {    solution S = solution ();    cout << s.ispalindrome ("1a2") << Endl;    return 1;}

　　

[Leetcode]valid palindrome