#include <bits/stdc++.h>

//#define int long long
#define ll long long
using namespace std;
void solve() {
    int n, k;
    std::cin >> n >> k;
    std::vector<int> c(n);
    for (int i = 0; i < n; ++i) {
        std::cin >> c[i];
        c[i] -= i;
    }
    map<int,int> a, b;
    ll sa=0,sb=0;
    int ca=0,cb=0;
    function<void()>bd=[&](){
        while(cb-1>ca){
            int it=b.begin()->first;
            --b[it];sb-=it;--cb;
            if(b[it]==0)b.erase(it);
            ++a[it];sa+=it;++ca;
        }
        while(ca>cb){
            int it=a.rbegin()->first;
            --a[it];sa-=it;--ca;
            if(a[it]==0)a.erase(it);
            ++b[it];sb+=it;++cb;
        }
    };
    function<void(int)>add=[&](int x){
        if(b.empty()){++b[x];sb+=x;++cb;return;}
        if(x>=b.begin()->first){++b[x];sb+=x;++cb;}
        else{++a[x];sa+=x;++ca;}
        bd();
    };
    function<void(int)>del=[&](int x){
        if(x>=b.begin()->first){--b[x];sb-=x;--cb;if(b[x]==0)b.erase(x);}
        else {--a[x];sa-=x;--ca;if(a[x]==0)a.erase(x);}
        bd();
    };
    function<int()>ge=[&](){
        if(sa==0&&sb==0)return 0ll;
        return b.begin()->first*ca-sa+sb-b.begin()->first*cb;
    };
    int ans=1;
    for(int l=0,r=0;l<n;++l){
        //cout<<l<<" "<<r<<" "<<ge()<<"\n";
        if(ge()<=k){
            while(r<n){
                add(c[r]);
                ++r;
                if(ge()>k)break;
            }
            if(ge()>k){--r;del(c[r]);}
            ans=max(ans,r-l);
        }
        del(c[l]);
    }
    cout<<ans<<"\n";
}

/*
5
7 5
7 2 5 5 4 11 7
6 0
100 3 4 5 99 100
5 6
1 1 1 1 1
5 50
100 200 300 400 500
1 100
3
*/

signed main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    int t = 1;
    std::cin >> t;
    for (int i = 0; i < t; ++i) {
        solve();
    }
    return 0;
}