#include <bits/stdc++.h>

using namespace std;

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

#define ABS(x) ((x) > 0 ? (x) : -(x))

int main() {
    cin.tie(0)->sync_with_stdio(0);

    int t;
    cin >> t;

    while(t--) {
        int n;
        cin >> n;

        ll k;
        cin >> k;

        vi a(n);
        for(int i = 0; i < n; i++) {
            cin >> a[i];
        }

        ll used = 0, shift = 0, abs = 0, ans = 1;
        vector<ll> srel;
        map<ll, ll> below, middle, above;

        const auto center = [&]() {
            if((ll)above.size() - (ll)below.size() - (ll)middle.size() > 0) {
                ll delta = above.begin()->first + shift;
                
                abs -= delta;
                shift -= delta;
                used -= ((ll)above.size() - (ll)below.size() - (ll)middle.size()) * delta;

                if(middle.size()) {
                    below[middle.begin()->first] += middle.begin()->second;
                    middle.clear();
                }

                middle[above.begin()->first] = above.begin()->second;
                above.erase(above.begin());
            } else if((ll)below.size() - (ll)above.size() - (ll)middle.size() > 0) {
                ll delta = below.rbegin()->first + shift;
                
                abs -= delta;
                shift -= delta;
                used -= ((ll)below.size() - (ll)above.size() - (ll)middle.size()) * -delta;

                if(middle.size()) {
                    above[middle.begin()->first] += middle.begin()->second;
                    middle.clear();
                }

                middle[below.rbegin()->first] = below.rbegin()->second;
                below.erase(below.rbegin()->first);
            }
        };

        abs = a[0];
        middle[0]++;
        srel.push_back(0);

        for(ll l = -1, r = 1; r < n; r++) {
            ll diff = abs + 1 - a[r];

            if(diff > 0) {
                above[diff - shift]++;
                used += diff;
                abs++;

                srel.push_back(diff - shift);
            } else if(diff == 0) {
                middle[diff - shift]++;
                abs++;
                used += diff;
                srel.push_back(diff - shift);
            } else {                
                below[diff - shift]++;
                used -= diff;
                abs++;

                srel.push_back(diff - shift);
            }

            center();

            if(used > k) {
                l++;

                used -= ABS(srel[l] + shift);

                if(srel[l] + shift > 0) {
                    above[srel[l]]--;

                    if(!above[srel[l]])
                        above.erase(srel[l]);
                } else if(srel[l] + shift == 0) {
                    middle[srel[l]]--;

                    if(!middle[srel[l]])
                        middle.erase(srel[l]);
                } else {
                    below[srel[l]]--;

                    if(!below[srel[l]])
                        below.erase(srel[l]);
                }

                center();
            }

            if(used <= k)
                ans = max(ans, r - l);
        }

        cout << ans << "\n";
    }
}