#include <bits/stdc++.h>
using namespace std;
#define int long long
#define double long double
typedef long long ull;
typedef unsigned long long uull;
typedef pair<int, int> PII;
mt19937 rnd1(random_device{}());
mt19937_64 rnd2(random_device{}());
uniform_int_distribution<int> dist1(0,2e18);    //定义dist1为0——100的随机整数
uniform_real_distribution<double> dist2(-10,10);    //定义dist2为-10——10的随机浮点数
//#define mp make_pair
//fflush(stdout);
inline void print(__int128 x){//输出模板 
    if(x<0){
        putchar('-');
        x=-x;
    }
    if(x>9) print(x/10);
    putchar(x%10+'0');
}
inline int read()
{
    int X = 0;
    bool flag = 1;
    char ch = getchar();
    while (ch < '0' || ch > '9')
    {
        if (ch == '-')
            flag = 0;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9')
    {
        X = (X << 1) + (X << 3) + ch - '0';
        ch = getchar();
    }
    if (flag)
        return X;
    return ~(X - 1);
}
const ull mod = 998244353,INF = 2e18;
ull qpow(ull a, ull b)
{
    ull res = 1;
    a %= mod;
    assert(b >= 0);
    for (; b; b >>= 1)
    {
        if (b & 1)
            res = res * a % mod;
        a = a * a % mod;
    }
    return res;
}
inline int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }
inline int lcm(int a, int b) { return a / gcd(a, b) * b; }
const int N = 500010,M = 200100;

int a[N];
multiset<int> q1,q2;

int check()
{
    auto it = q2.begin();
    int m = (int)*it;
    if(q1.size()>=q2.size())
    {
        it = q1.end();
        it--;
        m = (int)*it;
        q1.erase(it);
        q2.insert(m);
    }
    else if(q2.size()-q1.size()==2)
    {
        it = q2.begin();
        m = (int)*it;
        q1.insert(m);
        q2.erase(it);
        m = (int)*q2.begin();
    }
    return m;
}

void solve()
{
    int n,k;
    q1.clear(),q2.clear();
    cin>>n>>k;
    for(int i=1;i<=n;i++) cin>>a[i],a[i] -= i;
    int sum1 = 0,sum2 = 0,l = 1,ans = 1,cnt1 = 0,cnt2 = 0;
    if(a[1]>0) sum1 = a[1],cnt1 = 1;
    else sum2 = a[1],cnt2 = 1;
    q2.insert(a[1]);
    for(int i=2;i<=n;i++)
    {
        if(a[i]>0) sum1 += a[i],cnt1++;
        else sum2 += a[i],cnt2++;
        int mid = check();
        if(a[i]<mid) q1.insert(a[i]);
        else q2.insert(a[i]);
        mid = check();
        int len = i-l+1;
        if(abs(mid*cnt2-sum2)+abs(mid*cnt1-sum1)<=k) ans = max(ans,len);
        else 
        {
            while(1)
            {
                if(a[l]>0) sum1 -= a[l],cnt1--;
                else sum2 -= a[l],cnt2--;
                if(q1.find(a[l])!=q1.end())q1.erase(q1.find(a[l]));
                else q2.erase(q2.find(a[l])); 
                mid = check();
                l++;
                len = i-l+1;
                if(abs(mid*cnt2-sum2)+abs(mid*cnt1-sum1)<=k) break;
            }
            ans = max(ans,i-l+1);
        }
    }
    cout<<ans<<endl;
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
    cin>>t;
    while (t--)
        solve();
    return 0;
}