I am unable to understand why the my solution is wrong (failing on test case 2) for the this question: 2072C - Creating Keys for StORages Has Become My Main Skill Can someone please explain what am i missing here?

#include <bits/stdc++.h>
using namespace std;
#define dbg(v) \
    cerr << "Line(" << __LINE__ << ") -> " << #v << " = " << (v) << endl;


#define int long long

void scanarr(int arr[], int n)
{
    for(int i = 0; i < n; i++)
        cin >> arr[i];
}

int order(int x){   
    int ans = 0;
    while(x!=0){
        if(x/2 != 0) ans++;
        x /= 2;
    }
    return ans;
}

int32_t main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    
    int t;
    cin>>t;
    while(t--){
        int n,x;
        cin>>n>>x;
        int p=0, x1=x;
        while(x1!=0){
            if(x1%2 == 0) break;
            p++;
            x1 /= 2;
        }//cout<<p<<'\n';
        int a[31];
        a[0] = 1;
        for(int i=1; i<31; i++){
            a[i] = a[i-1]*2;
        }
        int mex = a[p];
        if(mex >= n){
            for(int i=0; i<n-1; i++){
                cout<<i<<" ";
            }
            if(order(n-1) == order(x)) cout<<n-1<<'\n';
            else cout<<x<<'\n';
        }else{
            for(int i=0; i<n-1; i++){
                if(i>= mex){
                    cout<<0<<" ";
                }else   
                {
                    cout<<i<<" ";
                }
            }cout<<x<<'\n';
        }
    }
    return 0;
}