#include<iostream>
#include<cmath>
#define ll unsigned long long
using namespace std;
int ispalindrome(ll int a)
{
    ll int temp=a;
    int n=0;
    while(temp){temp/=10;n++;}
    int arr[n];
    for(int i=0;i<n;i++)
    {
        arr[n-i-1]=a%10;
        a/=10;
    }
    int flag=0;
    for(int i=0;i<n/2;i++)
    {
        if(arr[n-i-1]!=arr[i])
        {
            flag++;break;
        }
    }
    if(flag==0){return 1;}
    else{return 0;}
}
int main()
{
    int test;cin>>test;
    while(test--)
    {
        ll int n;cin>>n;
        ll int i=1;
        while(1)
        {
            if(ispalindrome(n+i)==1){cout<<n+i<<endl;break;}
            i++;
        }
    }
}

I have tried a lot of test cases. Where have I gone wrong?