AND-AND-AND

#include<bits/stdc++.h>

using namespace std  ; 

using ll = long long  ;

#define ln "\n" ; 

void solve(){
    ll n,k  ;
     cin>>n>>k  ; 
     vector<ll>A(n) ; 
     for(int i =0;i<n;i++){
         cin>>A[i] ; 
     }
    vector<vector<ll> >prefix(n,vector<ll>(31,0)) ; 
    for(int i = 0 ;i<n;i++){
        for(int j = 0 ;j<31;j++){
            if((A[i]>>j)&1){
                prefix[i][j]++ ; 
            }
        }
    }
    for(int i = 1;i<n;i++){
        for(int j = 0 ;j<31;j++){
            prefix[i][j]+=prefix[i-1][j]   ; 
        }
    }
    vector<vector<ll> >nxt(n,vector<ll>(31,n)) ; 
    for(int i = n-1;i>=1;i--){
        for(int j = 0 ;j<31;j++){
            if((A[i]>>j)&1){
                nxt[i-1][j] = nxt[i][j] ; 
            }else{
                nxt[i-1][j] = i  ; 
            }
        }
    }
    ll ans = 1e9  ; 
    for(int i = 0 ;i<n;i++){
        ll val = A[i] ; 
        vector<ll>temp  ; 
        temp.push_back(i) ; 
        for(int j =0;j<31;j++){
            ll x = nxt[i][j] ; 
            if(x!=n){
                temp.push_back(x) ; 
            }
        }
        ll l = i  ; 
        for(int j =0;j<temp.size();j++){
            ll r = temp[j] ; 
            ll sub_ans = 0 ; 
            for(int z = 0;z<31;z++){
                ll y1 = prefix[r][z] ; 
                if(l-1>=0){
                    y1-= prefix[l-1][z] ; 
                }
                if(y1==(r-l+1)){
                    sub_ans|=(1<<z) ; 
                }
            }
            ans = min(ans,abs(sub_ans-k)) ; 
        }
    }
    cout<<ans<<ln  ; 
    
}

int main()
{
    ios_base::sync_with_stdio(false) ; 
    cin.tie(NULL) ; 
    cout.tie(NULL)  ; 
    ll t;
    cin >> t;
    for(int it=1;it<=t;it++) {
    // cout << "Case #" << it+1 << ": ";
        solve();
    }
    return 0;
}