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leetcode 0125

admin 11月 13, 2020 0

Desicription

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:
Have you consider that the string might be empty? This is a good question to ask during an interview.

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

Solution

class  {
public:
    bool isPalindrome(string s) {
        string res = "";
        for(auto it : s) {
            if((it >= 'a' && it <= 'z') || (it >= '0' && it <= '9'))
                res += it;
            else if(it >= 'A' && it <= 'Z')
                res += it + 'a' - 'A';
        }
        for(int i = 0, j = res.size()-1; i <= j; i++, j--) {
            if(res[i] != res[j])
                return 0;
        }
        return 1;
    }
};