#include <bits/stdc++.h>
#include "books.h"
using namespace std;
using ll = long long;
void solve(int n, int k, ll a, int s){
vector<pair<int, ll>> x;
pair<int, ll> big = {0, 0};
for(int i=1; i<=n; i++){
ll cur = skim(i);
big = {i, cur};
if(cur <= a){
x.push_back({i, cur});
} else break;
}
vector<int> ans;
ll sum = 0;
if((int) x.size() < k - 1){
impossible();
return;
}
for(int i=0; i<(k - 1); i++) sum += x[i].second;
if(a <= sum + big.second && sum + big.second <= 2 * a){
for(int i=0; i<(k - 1); i++) ans.push_back(x[i].first);
ans.push_back(big.first);
answer(ans);
return;
}
int l = 0;
for(int i=(k - 1); i<x.size(); i++){
sum += x[i].second;
if(a <= sum && sum <= 2 * a){
for(int j=l; j<=i; j++) ans.push_back(x[j].first);
answer(ans);
return;
}
sum -= x[l].second;
l ++;
}
impossible();
}
