Week Day 3 August 2020 leetcode challenge

valid-palindrome.cpp

class Solution {
    void printArray(vector<char> arr){
        cout<<"[";
        for(auto c: arr){
            cout<<c<<",";
        }
        cout<<"]"<<endl;

    }
    vector<char> stringToArrLower(string s){
         vector<char> arr;
        for(auto ch: s){
            
            if(isalnum(ch)){
                char next = isalpha(ch) ? tolower(ch) : ch;
                arr.push_back(next);
            }
        }
        return arr;
    }
public:
    //runtime : O(1) | space: O(n)
    bool isPalindrome(string s) {
        vector<char> arr;
        
        arr = stringToArrLower(s);

        int l = 0;
        int r = arr.size()-1;
       while(l<r){
           if(arr.at(l) != arr.at(r)){
               return false;
           }
           l++;
           r--;
       }
        return true;
    }
};