Haskell

import Control.Applicative
import Control.Monad
import System.IO
import Data.Set (Set)
import qualified Data.Set as Set

palindrome :: [Int]
palindrome = [x*y |
    y <- [100 .. 999], 
    x <- [y .. 999],  
    (x*y) <= 1000000, 
    (x*y) == read (reverse (show (x*y)))]
    
cap :: [Int] -> Int -> [Int]    
cap xs n = filter (<n) xs
    
findMax :: [Int] -> Int
findMax [x] = x
findMax (x:y:xs)
    | x > y = findMax (x:xs)
    | otherwise = findMax (y:xs)

main :: IO ()
main = do
    t_temp <- getLine
    let t = read t_temp :: Int
    forM_ [1..t] $ \a0  -> do
        n_temp <- getLine
        let n = read n_temp :: Int
        let palList = cap palindrome n
        putStrLn(show (findMax palList))

****def l_pal(n): s=[] for i in range(101,1000): for j in range(121,1000,(1 if i%11==0 else 11)): product = i*j if int(str(product)[::-1]) == product: if product

if name == 'main': t = int(input().strip())

for t_itr in range(t):
    n = int(input().strip())
    print(l_pal(n))

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;
            }
        }
    }

}