#include <bits/stdc++.h>
#include "books.h"
//#define int long long
#define ll long long
#define pb push_back
#define fs first
#define sc second
using namespace std;
void solve(int n, int k, long long a, int s){
vector<int> vec;
ll sum = 0;
for(int i = 1; i <= k; i++){
int v = skim(i); vec.pb(v), sum += v;
}
for(int i = max(k + 1, n - k + 1); i <= n; i++) vec.pb(skim(i));
if(sum > 2 * a) impossible();
int r = k, l = 1;
vector<int> res;
while(r < n){
sum -= vec[l];
r++;
sum += vec[r];
if(sum >= a and sum <= 2 * a){
for(int i = l; i <= r; i++) res.pb(i);
answer(res);
}
l++;
}
if(sum < a) impossible();
int val;
l = 1, r = n;
while(l <= r){
int mid = (l + r) / 2;
int v = skim(mid);
if(v > a) r = mid - 1;
else l = mid + 1, val = v;
}
vector<int> vec1;
for(int i = 0; i < k; i++) vec1.pb(vec[i]);
for(int i = max(k + 1, l - k); i < l; i++) vec1.pb(skim(i));
r = k, l = 1;
while(r < n){
sum -= vec1[l];
r++;
sum += vec1[r];
if(sum >= a and sum <= 2 * a){
for(int i = l; i <= r; i++) res.pb(i);
answer(res);
}
l++;
}
sum = 0;
vec1.clear();
for(int i = 0; i < k - 1; i++) sum += vec[i], vec1.pb(i);
sum += val;
vec1.pb(l);
if(sum < 2 * a) answer(vec1);
impossible();
}
