Palindrome Numbers

• Time : $O(nlog{10}n)$
• Space : $O(1)$

bool pal(int r) {
    string s = to_string(r);
    int i = 0, j = s.length() - 1;
    while(i < j) {
        if(s[i] != s[j]) return false;
        i++,j--;
    }
    return true;
}
int Solution::solve(int A, int B, int C) {
    int res = 0, now = 0, l = A, r = A;
    while(r < B) {
        while(r <= B and r - l <= C) {
            if(pal(r)) now++;
            if(r - l <= C) res = max(res, now);
            r++;
        }
        while(l < r and r - l > C) {
            if(pal(l)) now--;
            l++;
        }
    }
    return res;
}