#include "bits/stdc++.h"
using namespace std;
#include "books.h"
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
#define ll long long
#define mod 1000000007
void solve(int n, int k, ll a, int S) {
ll arr[n + 1];
for(int i = 1; i <= n; i++)
arr[i] = skim(i);
ll sum = 0;
bool b[n + 1];
for(int i = n; i >= n - k + 1; i--) {
sum += arr[i];
b[i] = 1;
}
if(sum >= a && sum <= 2 * a) {
vector<int> ans;
for(int i = n - k + 1; i <= n; i++)
ans.push_back(i);
answer(ans);
return;
}
if(sum < a) {
impossible();
return;
}
set<pair<ll, int>> s;
for(int i = 1; i < n - k + 1; i++)
s.insert({arr[i], i});
int j = n - k;
for(int i = n; i >= n - k + 1 && j >= 1; i--) {
auto it = s.lower_bound({(2 * a) - sum, 0});
if(it != s.end()) {
pair<ll, int> p = *it;
sum -= arr[i];
sum += p.first;
b[i] = 0, b[p.second] = 1;
}
if(sum >= a && sum <= 2 * a) {
vector<int> ans;
for(int i = 1; i <= n; i++) {
if(b[i])
ans.push_back(i);
}
answer(ans);
return;
}
}
impossible();
}
