C++ code

#include <cmath>
#include <cstdio>
#include <iostream>
using namespace std;

bool palindrome(int n){
    string s(to_string(n));
    int l= s.length();
    for(int i=0;i<l/2;i++){
        if(s[i] != s[l-i-1]) return false;
    }
    return true;
}

int find_max(int n){
    int max= 0;
    int produit;
    for(int n1=100;n1<1000;n1++){
        for(int n2=n1;n2<1000;n2++){
            produit=n1*n2;
            if(produit > max && produit < n && palindrome(produit))
               max=produit;
       }
    }
    return max;
}


int main() {
    int T, N;
    cin >> T;
    for(int i=0; i< T; i++){
        cin >> N;
        cout << find_max(N) << endl;
    }   
    return 0;
}

def is_palindrome(n): return str(n) == str(n)[::-1] def checker(k): for i in range(999, 99, -1):
if k % i == 0 and 100 <= k // i <= 999: return True return False

def main(): t = int(input()) for _ in range(t): n = int(input()) for i in range(n - 1, 101101 - 1, -1): if is_palindrome(i) and checker(i): print(i) break

if name == "main": main()

public static void main(String[] args) {

        List<Integer> list=new ArrayList<>();
        String x;
        StringBuilder sb;
        int ori;
        for(int i=999;i>=100;i--){
            for(int j=999;j>=100;j--){
                ori=i*j;
                x=String.valueOf(ori);
                sb=new StringBuilder(x);
                sb=sb.reverse();
                if(x.equals(sb.toString())){
                    list.add(ori);
                }
            }
        }
        Collections.sort(list,Collections.reverseOrder());


    Scanner in = new Scanner(System.in);
    int t = in.nextInt();
    for(int a0 = 0; a0 < t; a0++){
        int n = in.nextInt();
        for(int i=0;i<list.size();i++){
            if(list.get(i)<n){
                System.out.println(list.get(i));
                break;
            }
        }
    }

}

public class Solution {

public static void main(String[] args) {

    int l = 0;
    int f1 = 100;
    int limit = 999;
    int f2 =0;
    int smallest = 0;
    int[] arr;

    Scanner in = new Scanner(System.in);
    l = in.nextInt();
    arr = new int[l];

    for (int i = 0; i < l; i++) {

// Pattern pttr = Pattern.compile("\d\d\d\d\d\d"); // Matcher m = pttr.matcher(String.valueOf()); // if (!m.matches()) { // // continue; // // } else { // // smallest = l; // //System.out.println(i); // //System.out.println(temp/i); // // // }

        arr[i]=in.nextInt();

    }

    for (int k = 0; k < 2; k++) {

        l=arr[k];

        while(true) {

            if(checkPalindrome(l)) {

                for(int i = f1 ; i<limit ; i++) {

                    if(l%i == 0) {



                        int temp = l;



                        Pattern pttr = Pattern.compile("\\d\\d\\d");
                        Matcher m = pttr.matcher(String.valueOf(temp/i));
                        if (!m.matches()) {

                            continue;

                        } else {

                            smallest = l;
                            //System.out.println(i);
                            //System.out.println(temp/i);


                        }


                        break;

                    }

                }

            }

            l=l-1;



            if (l<100000) {

                break;


            }

            if (smallest!=0) {

                break;

            }

        }

        System.out.println(smallest);
        smallest = 0;



    }





}



public static boolean checkPalindrome(int n) {

    String s = String.valueOf(n);

    if(s.charAt(0) == s.charAt(s.length()-1)) {

        int r = 0;
        int sum = 0;
        int temp = n;

        while (n>0) {

            r=n%10;  //getting remainder
            sum=(sum*10)+r;
            n=n/10;
        }

        if (temp == sum) {

            return true;
        }


    }

    return false;



}

}