Gift

input/code.cpp: In function 'int main()':
input/code.cpp:177:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 0; j < mov[i].size(); ++j) {
                  ~~^~~~~~~~~~~~~~~

#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <unordered_map>
#include <math.h>

using namespace std;

const int N = 1e6 + 5;
const int M = 131072;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define F first
#define S second

ll t[N];

set<pll> s;

vector<ll> mov[2*N];


int main() {
/*	set<int> se;
	for(int i = 1; i <= 10; ++i) {
		se.insert(i);
	}
	int cou = 3;
	int ii = 0;
	set<int>::iterator iter = se.begin();
	while(ii < cou) {
		se.erase(iter);
		cout << *iter << "\n";
		se.insert((*iter) - 3);
		++ii;
		++iter;
	}

	for(iter = se.begin(); iter != se.end(); ++iter) {
		cout << *iter << " ";
	}
	cout << "\n";
	return 0;
*/	

	cin.tie(0);
	iostream::sync_with_stdio(false);
	int n, k;
	cin >> n >> k;
	ll sum = 0;
	for(int i = 1; i <= n; ++i) {
		ll a; cin >> a; t[i] = a;
		s.insert({a, i});
		sum += a;
	}

	if(sum%k != 0) {
		cout << -1 << "\n";
		return 0;
	}

	for(int i = 1; i <= n; ++i) {
		if(t[i] > sum/k) {
			cout << -1 << "\n";
			return 0;
		}
	}

	if(n == k) {
		for(int i = 1; i <= n; ++i) {
			if(t[i] != sum/k) {
				cout << -1 << "\n";
				return 0;
			}
		}
		cout << 1 << "\n";
		cout << sum/k << " ";
		for(int i = 1; i <= n; ++i) {
			cout << i << " ";
		}
		cout << "\n";
		return 0;
	}

	ll c = 0;
	
	if(k > n/100) {
		vector<pll> v;
		v.push_back({-1, -1});
		for(int i = 1; i <= n; ++i) {
			v.push_back({t[i], i});
		}
		sort(v.begin(), v.end());
		while(sum > 0 && c*k <= 3000000) {
			ll x = min(sum/k - v[n-k].first, v[n-k+1].first);
			mov[c].push_back(x);
			for(int i = n-k+1; i <= n; ++i) {
				v[i] = {v[i].first - x, v[i].second};
				mov[c].push_back(v[i].second);
			}
			sort(v.begin(), v.end());
			sum -= x*k;
			++c;
		}
	} else {
		while(sum > 0 && c*k <= 1000000) {
			ll k1th;
			set<pll>::iterator it;
			if(k < n/2) {
				it = s.end();
				--it;
				int i = n;
				while(i != n - k) {
					--it;
					--i;
				}
			} else {
				it = s.begin();
				int i = 1;
				while(i != n-k) {
					++it;
					++i;
				}
			}
	/*		k1th = (*it).first;
			++it;
		//	cout << "Sum : " << sum << " and k+1:th largest is " << k1th << "\n";
			ll x = min(sum/k - k1th, (*it).first);
			it = s.end();
			vector<pll> ne;
			mov[c].push_back(x);
			for(int i = n; i > n-k; --i) {
				--it;
				ne.push_back({(*it).first - x, (*it).second});
				mov[c].push_back((*it).second);
			}
	*/


			k1th = (*it).first;
			++it;
		//	cout << "Sum : " << sum << " and k+1:th largest is " << k1th << "\n";
			ll x = min(sum/k - k1th, (*it).first);
			vector<pll> ne;
			mov[c].push_back(x);
			for(int i = n - k + 1; i <= n; ++i) {
				s.insert({(*it).first - x, (*it).second});
				mov[c].push_back((*it).second);
				set<pll>::iterator ite = it;
				++it;
				s.erase(ite);
			}

	/*		for(int i = n; i > n-k; --i) {
				it = s.end();
				--it;
				s.erase(it);	
			}
			for(int i = 0; i < ne.size(); ++i) {
				s.insert(ne[i]);
			}
	*/		sum -= x*k;
			++c;
		}
	}
	if(sum != 0) {
		cout << -1 << "\n";
		return 0;
	}

	cout << c << "\n";
	for(int i = 0; i < c; ++i) {
		for(int j = 0; j < mov[i].size(); ++j) {
			cout << mov[i][j] << " ";
		}
		cout << "\n";
	}
}

Test 1

Group: 1, 2, 3, 5

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3, 5

Verdict: ACCEPTED

Test 3

Group: 1, 2, 3, 5

Verdict: ACCEPTED

Test 4

Group: 1, 2, 3, 5

Verdict: ACCEPTED

Test 5

Group: 1, 2, 3, 5

Verdict: ACCEPTED

Test 6

Group: 1, 2, 3, 5

Verdict: ACCEPTED

Test 7

Group: 1, 2, 3, 5

Verdict: ACCEPTED

Test 8

Group: 2, 3, 5

Verdict: ACCEPTED

Test 9

Group: 2, 3, 5

Verdict: ACCEPTED

Test 10

Group: 2, 3, 5

Verdict: ACCEPTED

Test 11

Group: 2, 3, 5

Verdict: ACCEPTED

Test 12

Group: 2, 3, 5

Verdict: ACCEPTED

Test 13

Group: 2, 3, 5

Verdict: ACCEPTED

Test 14

Group: 2, 3, 5

Verdict: ACCEPTED

Test 15

Group: 2, 3, 5

Verdict: ACCEPTED

Test 16

Group: 2, 3, 5

Verdict: ACCEPTED

Test 17

Group: 3, 5

Verdict: ACCEPTED

Test 18

Group: 3, 5

Verdict: ACCEPTED

Test 19

Group: 3, 5

Verdict: ACCEPTED

Test 20

Group: 3, 5

Verdict: ACCEPTED

Test 21

Group: 3, 5

Verdict: ACCEPTED

Test 22

Group: 3, 5

Verdict: ACCEPTED

Test 23

Group: 4, 5

Verdict: ACCEPTED

Test 24

Group: 4, 5

Verdict: ACCEPTED

Test 25

Group: 4, 5

Verdict: ACCEPTED

Test 26

Group: 4, 5

Verdict: ACCEPTED

Test 27

Group: 4, 5

Verdict: ACCEPTED

Test 28

Group: 4, 5

Verdict: ACCEPTED

Test 29

Group: 4, 5

Verdict: ACCEPTED

Test 30

Group: 4, 5

Verdict: ACCEPTED

Test 31

Group: 4, 5

Verdict: ACCEPTED

Test 32

Group: 4, 5

Verdict: ACCEPTED

Test 33

Group: 4, 5

Verdict: ACCEPTED

Test 34

Group: 5

Verdict: ACCEPTED

Test 35

Group: 5

Verdict: ACCEPTED

Test 36

Group: 5

Verdict: ACCEPTED

Test 37

Group: 4, 5

Verdict: ACCEPTED

Test 38

Group: 5

Verdict: ACCEPTED

Test 39

Group: 5

Verdict: ACCEPTED

Test 40

Group: 5

Verdict: ACCEPTED

Test 41

Group: 5

Verdict: ACCEPTED

Test 42

Group: 5

Verdict: ACCEPTED

Test 43

Group: 5

Verdict: WRONG ANSWER

Test 44

Group: 5

Verdict: TIME LIMIT EXCEEDED

Test 45

Group: 5

Verdict: WRONG ANSWER

Test 46

Group: 5

Verdict: ACCEPTED

Test 47

Group: 5

Verdict: ACCEPTED

Test 48

Group: 5

Verdict: WRONG ANSWER

Test 49

Group: 5

Verdict: WRONG ANSWER

Test 50

Group: 5

Verdict: ACCEPTED

Test 51

Group: 5

Verdict: ACCEPTED

Test 52

Group: 5

Verdict: ACCEPTED

Test 53

Group: 5

Verdict: ACCEPTED

Test 54

Group: 5

Verdict: ACCEPTED

Test 55

Group: 5

Verdict: ACCEPTED

Test 56

Group: 5

Verdict: ACCEPTED