#include<iostream>
#include<set>
#include<algorithm>
using namespace std;
typedef long long ll;
ll n,k,t;
ll a[500005],sum[500005];
int main()
{
    std::ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin>>t;
    while(t--)
    {
        cin>>n>>k;
        for(ll i=1;i<=n;i++)
            cin>>a[i],a[i]=a[i]-i+1;
        ll i=1,j=1,now=0,sum1=0,sum2=0,p=0,q=0,x=0,mx=1;
        multiset<ll> s2;
        multiset<ll,greater<ll>> s1;
        while(j<=n)
        {
            if(n-i+1<=mx)
                break;
            if((j-i+1)%2&&j-i+1!=1)//加入这个数后是奇数
            {
                x=a[j];
                p=*s1.begin();
                q=*s2.begin();
                s1.erase(s1.begin());
                s2.erase(s2.begin());
                sum1-=p;
                sum2-=q;
                if(p>x)
                    swap(p,x);
                if(x>q)
                    swap(x,q);
                s1.insert(p);
                s2.insert(q);
                sum1+=p;
                sum2+=q;
                now=s1.size()*x-sum1+sum2-s2.size()*x;
                s1.insert(x);
                sum1+=x;
            }
            else if((j-i+1)==1)//加入这个数后是一个数
            {
                s1.insert(a[j]);
                sum1+=a[j];
            }
            else if((j-i+1)==2)
            {
                p=*s1.begin();
                s1.erase(s1.begin());
                sum1-=p;
                q=a[j];
                now=max(p,q)-min(p,q);
                s1.insert(min(p,q));
                sum1+=min(p,q);
                s2.insert(max(p,q));
                sum2+=max(p,q);
            }
            else
            {
                x=a[j];
                p=*s1.begin();
                q=*s2.begin();
                s1.erase(s1.begin());
                s2.erase(s2.begin());
                sum1-=p;
                sum2-=q;
                bool flag=false;
                if(p>x)
                    swap(p,x);
                if(x>q)
                    swap(x,q);
                if(s1.size()>s2.size())
                    s2.insert(q),sum2+=q,flag=true;
                else
                    s1.insert(p),sum1+=p;
                if(!flag)
                    p=x,x=q;
                now=min(s1.size()*p-sum1+sum2-s2.size()*p+x-p,s1.size()*x-sum1+sum2-s2.size()*x+p-x);
                s1.insert(p);
                sum1+=p;
                s2.insert(x);
                sum2+=x;
            }
            while(now>k&&i<j)
            {
                x=a[i];
                if(x<=*s1.begin())
                {
                    auto it=s1.find(x);
                    s1.erase(it);
                    sum1-=x;
                }
                else
                {
                    auto it=s2.find(x);
                    s2.erase(it);
                    sum2-=x;
                }
                if(s1.size()<s2.size())
                {
                    s1.insert(*s2.begin());
                    sum1+=*s2.begin();
                    sum2-=*s2.begin();
                    s2.erase(s2.begin());
                }
                
                if((s1.size()+s2.size())%2)
                {
                    now=s1.size()*(*s1.begin())-sum1+sum2-s2.size()*(*s1.begin());
                }
                else
                {
                    now=min(s1.size()*(*s1.begin())-sum1+sum2-s2.size()*(*s1.begin()),
                    s1.size()*(*s2.begin())-sum1+sum2-s2.size()*(*s2.begin()));
                }
                i++;
            }
            mx=max(mx,j-i+1);
            j++;
        }
        cout<<mx<<"\n";
    }
    return 0;
}