class Solution {
public:
    bool checkSelfPalindrome(const string& a, int left, int right) {
        while (left < right and a[left] == a[right]) {
            left++;
            right--;
        }
        return left >= right;
    }
     bool checkConcatenation(const string& a, const string& b) {
        int n = a.size();
        int left = 0, right = n-1;
        while (left < right and a[left] == b[right]) {
            left++;
            right--;
        }
        if (left >= right) return true;
        return checkSelfPalindrome(a, left, right) or checkSelfPalindrome(b, left, right);
    }
    bool checkPalindromeFormation(string a, string b) {
        return checkConcatenation(a, b) or checkConcatenation(b, a);
    }
};