#include<bits/stdc++.h>
using namespace std;

#define FAST_IO             (ios_base:: sync_with_stdio(false),cin.tie(NULL));
#define ll                  long long
#define ull                 unsigned long long
#define endl                '\n'
#define ff                  first
#define ss                  second
#define pb                  push_back
#define all(x)              x.begin(), x.end()
#define sz(x)               (int)(x).size()
#define yes                 cout<<"YES"<<endl
#define no                  cout<<"NO"<<endl
#define neg1                cout<<-1<<endl
#define PI                  3.141592653589793238
#define MIN                 INT_MIN
#define MAX                 INT_MAX
#define INF                 LONG_LONG_MAX
#define MOD                 1000000007
#define LLM                 1000000000000000007

ll factorial(ll n)                        { if(n==0) return 1; ll res = 1; for (ll i = 2; i <= n; i++) res = res * i; return res; }
ll nPr(ll n, ll r)                        { return factorial(n) / factorial(n - r); }
ll nCr(ll n, ll r)                        { return factorial(n) / (factorial(r) * factorial(n - r));}
ll gcd(ll a, ll b)                        { if (b == 0) return a; return gcd(b, a % b); }
ll lcm(ll a, ll b)                        { return (a * b) / gcd(a, b);}
ull mypow(ull a, ull b,ull m=MOD)         { ull ans = 1; a%=m; while(b){ if (b&1) ans = (ans*a) % m; a = (a*a) % m; b >>= 1; } return ans; }
bool isPrime(ll n)                        { if(n <= 1) return false; for(ll i = 2; i*i <= n; i++) if(n % i == 0) return false; return true; }

#ifndef ONLINE_JUDGE
#define dbg(x...) cerr << #x << " : "; _print(x)
#else
#define dbg(...)
#endif
void __print(int x) {cerr << x;}void __print(long x) {cerr << x;} void __print(long long x){cerr << x;}
void __print(unsigned x){cerr << x;} void __print(unsigned long x){cerr << x;} void __print(unsigned long long x){cerr << x;}
void __print(float x){cerr << x;} void __print(double x){cerr << x;} void __print(long double x){cerr << x;}
void __print(char x){cerr << x;} void __print(const char *x){cerr << x;} void __print(const string &x){cerr << x;}
void __print(bool x){cerr << (x ? "true" : "false");} void _print() { cerr << "\n"; }
template <typename A> void __print(const A &x); template <typename A, typename B> void __print(const pair<A, B> &p);
template <typename A> void __print(const A &x) {bool f=1; cerr << '['; for (const auto &i : x) {cerr << (f ? "" : ","), __print(i); f = 0;} cerr << ']';}
template <typename A, typename B> void __print(const pair<A, B> &p) {cerr << '('; __print(p.first); cerr << ','; __print(p.second); cerr << ')';}
template <typename Head, typename... Tail> void _print(const Head &H, const Tail &...T) { __print(H); if (sizeof...(T)) cerr << ", "; _print(T...);}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

void solve()
{
    ll n,k;
    cin>>n>>k;
    deque<ll>d;
    for(int i=0; i<n; ++i)
    {
        int x;
        cin>>x;
        d.pb(x);
    }
    int f=1, ans=0;
    while(k>0 && sz(d))
    {
        if(sz(d)==1)
        {
            if(d.front()<=k)
                ans++;
            break;
        }
        int x=d.front();
        int y=d.back();
        int z=min(x,y);
        d.pop_front();
        d.pop_back();
        if(f)
        {
            if(z==x)
            {
                if(k<2*z-1)   break;
                k-=2*z-1;
                y-=z-1;
                f=0;
                d.push_back(y);
                ans++;
            }
            else
            {
                if(k<2*z)   break;
                k-=2*z;
                x-=z;
                d.push_front(x);
                ans++;
            }
        }
        else
        {
            if(z==y)
            {
                if(k<2*z-1)   break;
                k-=2*z-1;
                x-=z-1;
                f=1;
                d.push_front(x);
                ans++;
            }
            else
            {
                if(k<2*z)   break;
                k-=2*z;
                y-=z;
                d.push_back(y);
                ans++;
            }
        }
    }
    cout<<ans<<endl;
}

signed main()
{
    FAST_IO;
    int TC = 1;
    cin >> TC;
    while (TC--) 
        solve();
}