#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using VI = vector<int>;
using PII = pair<ll,ll>;
using VVI = vector<vector<int>>;
const ll mod = 998244353;
const ll INF = 1e18;
const int N = 1e5 + 10;


struct ds{
    ll b = 0,s = 0;
    multiset<ll> pb;
    multiset<ll,greater<ll>> ps;
    void insert(ll x){
        if(pb.size() == 0 || (*pb.begin()) <= x){
            //cout<<1;
            b += x;
            pb.insert(x);
        }else{
            s += x;
            ps.insert(x);
        }
        bal();
    }
    void bal(){
        if(pb.size() == 0) return;
        if(pb.size() < ps.size()){
            auto u = ps.begin();
            ps.erase(u);
            pb.insert(*u);
            s -= *u;
            b += *u;

        }else if(ps.size() < pb.size() - 1){
            auto u = pb.begin();
            pb.erase(u);
            ps.insert(*u);
            b -= *u;
            s += *u;

        }

    }

    ll mid(){
        if(pb.size() == 0) return 0;
        return *pb.begin();
    }

    ll query(){
        return b - (mid() * pb.size()) + (mid() * ps.size()) - s;

    }

    void del(ll x){
        if(pb.find(x) != pb.end()) {
            auto u = pb.find(x);
            pb.erase(u);
            b -= x;
        }else if(ps.find(x) != ps.end()){
            auto u = ps.find(x);
            ps.erase(u);
            s -= x;
        }
        bal();
    }

};


ll n,k;
int a[N];
void solve(){
    cin>>n>>k;
    for(int i = 1 ; i <= n ; i++){
        cin>>a[i];
        a[i] -= i;
    }
    ds s;
    int j = 0;
    int res = 1;
    for(int i = 1 ; i <= n ; i++){
        //if(i == 2) cout<<s.query()<<"\n";
        while(j <= n && s.query() <= k){
            j++;
            if(j > n) break;
            s.insert(a[j]);
           /* if(i == 1 && j == 2) {
            	cout<<s.pb.size()<<" ";
            	cout<<s.ps.size()<<" ";
            	cout<<s.b<<" "<<s.s<<" ";
            	cout<<s.mid()<<" ";
            	cout<<s.query()<<" ";
            }*/
        }
       	//cout<<i<<" "<<j<<"\n";
        res = max(res , j - i);
        s.del(a[i]);
    }
    cout<<res<<"\n";

}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int T;cin>>T;while(T--)solve();

}


//5 4 3 2 1
//5 4 3 2 1