#include <bits/stdc++.h>
typedef long long int ll;
#define endl            '\n'
#define pb             push_back
#define mp              make_pair
#define pll             pair<ll,ll> 
#define fill(x, y)     memset(x, y, sizeof(x))
#define all(x)         (x).begin(), (x).end()
#define debug(x)       { cerr << #x << " = " << x << endl; }
#define IO	       { ios_base::sync_with_stdio(false); cin.tie(0); }
#define read(x)	       freopen(x, "r", stdin)
#define write(x)       freopen(x, "w", stdout)


using namespace std;

typedef vector<int> vi;


double getAns(vector<ll> h, ll n, ll k, long double g) {
    ll m = g;

        vector<ll> c(n + 100);

        vector<pair<ll, ll>> arr, arr2;
        for (int i=0; i<n; i++) {
            c[i] = h[i] - m * i;
            arr.push_back({c[i], i});
            arr2.push_back({c[i], -i});
        }
        sort(all(arr));
        sort(all(arr2));

        ll max_i = 0;
        ll min_i = n;


        vector<ll> mx_nxt(n + 100, -1);

        for (int i= n - 1; i>=0; i--) {
            if (max_i > arr[i].second) mx_nxt[arr[i].second] = max_i;
            max_i = max(max_i, arr[i].second);
        }


        
        
        double ans = 0;
        for (int i=0; i<n; i++) {
            if (mx_nxt[i] != -1) {
                if (mx_nxt[i] == n-1) ans = max(ans, (double) (n - 1 - i) );
                else {
                    double x2 = mx_nxt[i];
                    double y2 = h[x2];
                    double x3 = x2+1;
                    double y3 = h[x3];
                    double x = y2 - c[i] - (y3 - y2) * x2;
                    if (m - y3 + y2 == 0) continue;
                    x /= (double) (m - y3 + y2);
                    ans = max(ans, x - (double)i);
                }
            }
        }
        return ans;
}

void solve() {
    ll n, k;
    cin >> n >> k;
    n++;

    vector<ll> h(n);
    for (int i=0; i<n; i++) {
        cin >> h[i];
    } 

    while(k--) {
        long double g;
        cin >> g;
        g *= 10.0;
        double a1 = getAns(h, n, k, g);
        reverse(all(h));
        for (ll &x: h) x = -x;
        double a2 = getAns(h, n, k, g);
        for (ll &x: h) x = -x;
        reverse(all(h));
        double a = max(a1, a2);
        if (a == 0) cout << "impossible" << endl;
        else cout << a << endl;
    }
}


int main() {
    //IO;
    cout << fixed << setprecision(10);
    solve();
}