#include<bits/stdc++.h>
#define ll long long 
#define pii pair<int,int>
#define pss pair<string,string>
#define fi first
#define se second
#define pb push_back
#define un unsigned
#define ull unsigned long long
#define	int_INF 0x3f3f3f3f
#define LL long long
#define ll_INF 0x3f3f3f3f3f3f3f3f
#define lb long double
#define db double
#define re return
#define pll pair<ll,ll>
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(),(x).end()
#define debug(a) cout<<"debug: "<<(#a)<<" = "<<a<<'\n'
#define cer(a) cerr<<#a<<'='<<(a)<<"@ line"<<__LINE__<<endl
#define cer2(a,b) cerr<<#a<<'='<<(a)<<','<<#b<<'='<<(b)<<"@ line"<<__LINE__<<endl
#define cer3(a,b,c) cerr<<#a<<'='<<(a)<<','<<#b<<'='<<(b)<<','<<#c<<'='<<(c)<<','<<"@ line"<<__LINE__<<endl
#define pdd pair<db,db>
#define Yes cout<<"Yes"<<'\n'
#define No cout<<"No"<<'\n'
#define KV(x) #x << " = " << x << ";"
#define DEBUG DebugLine(__LINE__)
#pragma GCC optimize("-fdelete-null-pointer-checks,inline-functions-called-once,-funsafe-loop-optimizations,-fexpensive-optimizations,-foptimize-sibling-calls,-ftree-switch-conversion,-finline-small-functions,inline-small-functions,-frerun-cse-after-loop,-fhoist-adjacent-loads,-findirect-inlining,-freorder-functions,no-stack-protector,-fpartial-inlining,-fsched-interblock,-fcse-follow-jumps,-fcse-skip-blocks,-falign-functions,-fstrict-overflow,-fstrict-aliasing,-fschedule-insns2,-ftree-tail-merge,inline-functions,-fschedule-insns,-freorder-blocks,-fwhole-program,-funroll-loops,-fthread-jumps,-fcrossjumping,-fcaller-saves,-fdevirtualize,-falign-labels,-falign-loops,-falign-jumps,unroll-loops,-fsched-spec,-ffast-math,Ofast,inline,-fgcse,-fgcse-lm,-fipa-sra,-ftree-pre,-ftree-vrp,-fpeephole2",3)
#pragma GCC target("avx","sse2")
using namespace std;
const int maxn=5e5+100;
const ll mode=998244353;
const ll mode2=1e9+7;
const ll inf=9223372036854775807;
const db eps=1e-6;
typedef pair<int,int> hashv;
mt19937 mrand(random_device{}()); 
hashv operator + (hashv a,hashv b) {
	int c1=a.fi+b.fi,c2=a.se+b.se;
	if (c1>=mode) c1-=mode;
	if (c2>=mode2) c2-=mode2;
	return mp(c1,c2);
}

hashv operator - (hashv a,hashv b) {
	int c1=a.fi-b.fi,c2=a.se-b.se;
	if (c1<0) c1+=mode;
	if (c2<0) c2+=mode2;
	return mp(c1,c2);
}

hashv operator * (hashv a,hashv b) {
	return mp(1ll*a.fi*b.fi%mode,1ll*a.se*b.se%mode2);
}
int rnd(int x) { return mrand() % x;}
struct DebugLine {
  explicit DebugLine(int lineno) { std::cerr << lineno << "L "; }
 
  ~DebugLine() { std::cerr << std::endl; }
 
  template <typename T> DebugLine &operator<<(T &&v) {
    std::cerr << std::forward<T>(v);
    return *this;
  }
};
double PI = 3.141592653;
double my_cos(double x){
    return cos(x*PI / 180.0);
}
double my_sin(double x){
    return sin(x*PI / 180.0);
}
double my_tan(double x){
    return tan(x*PI / 180.0);
}
ll n,m,a[maxn];
ll sum,ans;
string str;
vector<int>vt;
int vis[maxn]; 
ll ksm(ll a,ll b,ll p)
{
	ll res=1ll;
	while(b)
	{
		if(b&1)
		res=res*a%p;
		b>>=1;
		a=a*a%p;
	}
	return res;
}
struct Hash_char{
    const ll mod=998244353, base=131;
    ll p[maxn], g[maxn];
    void getp(){
        p[0]=1;
        for(int i=1; i<maxn; i++){
            p[i]=p[i-1]*base%mod;
        }
    }
    LL Hash(char s[]){
        int len=strlen(s+1);
        g[0]=0, g[1]=s[1];
        for(int i=2; i<=len; i++){
            g[i]=(g[i-1]*base+s[i])%mod;
        }
        return g[len];
    }
    LL getLR(int l, int r){//µÃµ½s[l]-s[r]µÄhashÖµ 
        if(l>r) return 0;
        LL ans=((g[r]-g[l-1]*p[r-l+1])%mod+mod)%mod;
        return ans;
    }
    
 
}T[2];
LL strfz(int pos, int l, int r){//pos:Õý·´´®,·­×ªl, r¡£ 
    LL ans=T[pos].getLR(1, l-1)*T[pos].p[n-l+1]%T[pos].mod;
    LL res=T[pos^1].getLR(n-r+1, n-r+1+r-l)*T[pos].p[n-r]%T[pos].mod;
    ans=ans+res+T[pos].getLR(r+1, n);
    return ans%T[pos].mod;
}

template<const int T>
struct ModInt {
    const static int mod = T;
    int x;
    ModInt(int x = 0) : x(x % mod) {}
    ModInt(long long x) : x(int(x % mod)) {} 
    int val() { return x; }
    ModInt operator + (const ModInt &a) const { int x0 = x + a.x; return ModInt(x0 < mod ? x0 : x0 - mod); }
    ModInt operator - (const ModInt &a) const { int x0 = x - a.x; return ModInt(x0 < 0 ? x0 + mod : x0); }
    ModInt operator * (const ModInt &a) const { return ModInt(1LL * x * a.x % mod); }
    ModInt operator / (const ModInt &a) const { return *this * a.inv(); }
    bool operator == (const ModInt &a) const { return x == a.x; };
    bool operator != (const ModInt &a) const { return x != a.x; };
    void operator += (const ModInt &a) { x += a.x; if (x >= mod) x -= mod; }
    void operator -= (const ModInt &a) { x -= a.x; if (x < 0) x += mod; }
    void operator *= (const ModInt &a) { x = 1LL * x * a.x % mod; }
    void operator /= (const ModInt &a) { *this = *this / a; }
    friend ModInt operator + (int y, const ModInt &a){ int x0 = y + a.x; return ModInt(x0 < mod ? x0 : x0 - mod); }
    friend ModInt operator - (int y, const ModInt &a){ int x0 = y - a.x; return ModInt(x0 < 0 ? x0 + mod : x0); }
    friend ModInt operator * (int y, const ModInt &a){ return ModInt(1LL * y * a.x % mod);}
    friend ModInt operator / (int y, const ModInt &a){ return ModInt(y) / a;}
    friend ostream &operator<<(ostream &os, const ModInt &a) { return os << a.x;}
    friend istream &operator>>(istream &is, ModInt &t){return is >> t.x;}
 
    ModInt pow(int64_t n) const {
        if(n == 0) return 1;
        ModInt res(1), mul(x);
        while(n){
            if (n & 1) res *= mul;
            mul *= mul;
            n >>= 1;
        }
        return res;
    }
     
    ModInt inv() const {
        int a = x, b = mod, u = 1, v = 0;
        while (b) {
            int t = a / b;
            a -= t * b; swap(a, b);
            u -= t * v; swap(u, v);
        }
        if (u < 0) u += mod;
        return u;
    }
     
};
using mint = ModInt<1000000007>;
ll ecgcd(ll a,ll b,ll& x,ll& y)
{
    if(b==0)
    {
        x=1,y=0;
        return a;
    }
    ll d=ecgcd(b,a%b,y,x);
    y-=a/b*x;
    return d;
}
class manacherWrapper
{
    private:
        int l_;
        string s_;
    public:
        std::vector<int> p;
        std::vector<int> b;
        std::vector<int> s;
        explicit manacherWrapper(string str)
        {
            auto l = str.size();
            //rebuild
            l_ = l;
            s_.resize(((l_ + 1) << 1) | 1);
            p.resize(((l_ + 1) << 1) | 1);
            b.resize(l_);
            s.resize(l_ + 1);
 
            s_[0] = '$', s_[1] = '#';
 
            for (int i = 0; i < l_; ++i)
                s_[(i + 1) << 1] = str[i], s_[((i + 1) << 1) | 1] = '#';
            l_ = (l_ + 1) << 1;
            //calc p
            int mx = 0, id;
            for (int i = 0; i < l_; ++i)
            {
                if (mx > i)p[i] = std::min(p[(id << 1) - i], mx - i);
                else p[i] = 1;
                for (; s_[i - p[i]] == s_[i + p[i]]; p[i]++);
                if (p[i] + i > mx)
                {
                    mx = p[i] + i;
                    id = i;
                }
            }
            //calc b and s
            for (int i = 0; i < l; ++i)
            {
                auto lp = get(i);
                b[i - (lp >> 1)] = std::max(b[i - (lp >> 1)], lp);
                s[i - (lp >> 1)]++, s[i + 1]--;
                if (i + 1 >= l)break;
                lp = get(i, i + 1);
                if (lp > 0)
                {
                    b[i + 1 - (lp >> 1)] = std::max(b[i + 1 - (lp >> 1)], lp);
                    s[i + 1 - (lp >> 1)]++, s[i + 1]--;
                }
            }
            for (int i = 1; i < l; ++i)
            {
                b[i] = std::max(b[i], b[i - 1] - 2);
                s[i] += s[i - 1];
            }
        }
 
        int get(int pos)
        {
            return (int) p[(pos + 1) << 1] - 1;
        }
 
        int get(int posl, int posr)
        {
            return (int) p[((posl + 1) << 1) | 1] - 1;
        }
 
        int longestBegin(int begin)
        {
            return b[begin];
        }
 
        int totalBegin(int begin)
        {
            return s[begin];
        }
 
        bool isPalindrome(int l,int r)
        {
            if (l > r)std::swap(l, r);
            auto mid = (l + r) >> 1;
            auto len = (r - l + 1);
            return len & 1 ? get(mid) >= len : get(mid, mid + 1) >= len;
        }
};
ll k;
ll pre[maxn],b[maxn];
ll check(int l,int r)
{
	ll v=pre[r]-pre[l-1];
	return v;
}
void solve()
{
   cin>>n>>k;
   for(int i=1;i<=n;i++)
   {
   	 cin>>a[i];
   }
   if(n==1)
   {
   	 cout<<1<<'\n';
   	 return;
   }
   ans=1;
   a[0]=0;
   for(int i=n;i>=1;i--)
   {
   	 a[i]=a[i]-a[i-1];
   }
   for(int i=1;i<=n;i++)
   {
   	 b[i]=abs(a[i]-1);
   }
   for(int i=1;i<=n;i++)
   {
   	 pre[i]=pre[i-1]+b[i];
   }
   for(int i=1;i<=n;i++)
   {
   	   int l=i,r=n;
   	   int pos=-1;
   	   while(l<=r)
   	   {
   	      int mid=(l+r)>>1;
   	      ll need=check(i,mid);
   	      if(i==1)
   	      need-=a[1];
		  if(need<=k)
		  {
		     pos=max(pos,mid);
			 l=mid+1;	
		  }else r=mid-1;
	   }
	   if(pos==-1)
	   continue;
	   ll v=pos-i+1ll+(i!=1?1:0);

	   ans=max(ans,v);
   }
   cout<<ans<<'\n';
}
int main(){
	#ifndef ONLINE_JUDGE
		freopen("C:\\Users\\JIAJIEASHI\\Desktop\\in.cpp","r",stdin);
	//	freopen("out.cpp","w",stdout);
	#endif
    ios::sync_with_stdio(false);
	cin.tie(0);cout.tie(0);
	int test_case;
	test_case=1;
	cin>>test_case;
	while(test_case--) 
    solve();
	return 0;
}