Submission #501018

#	Time	Username	Problem	Language	Result	Execution time	Memory
501018		dostigator	Gift (IZhO18_nicegift)	C++17	7 / 100	2081 ms	80480 KiB

nicegift

// author lox:(
#pragma GCC optimize("O3")
#pragma GCC target("popcnt")
#include <bits/stdc++.h>
using namespace std;
#define popcnt __builtin_popcount
#define all(a) a.begin(),a.end()
#define low_b lower_bound
#define up_b upper_bound
#define vii vector<pair<ll,ll>>
#define vll vector<pair<ll,ll>>
#define pii pair<ll,ll>
#define mii map<ll,ll>
#define pll pair<ll,ll>
#define mll map<ll,ll>
#define vi vector<ll>
#define vl vector<ll>
#define pb push_back
#define endl '\n'
#define Y second
#define X first
typedef long double ld;
typedef long long ll;
const ll dx[4]={1,-1,0,0},dy[4]={0,0,1,-1},col=107,N=3e6+777;
const ll mod=1e9+7,inf=1e18;
void fre_open(){freopen("file.in","r",stdin);freopen("file.out","w",stdout);}
ll binpow(ll n,ll k){if(k<0)return 0ll;if(k==0)return 1ll;if(k%2)return (binpow(n,k-1)*n)%mod;ll kk=binpow(n,k/2)%mod;return (kk*kk)%mod;}
void solve(){
	int n,k,sum=0;
	cin>>n>>k;
	int a[n+1];
	set<pii>s;
	for(int i=1; i<=n; ++i){
        cin>>a[i];
		s.insert({a[i],i});
        sum+=a[i];
	}
	if(sum%k) {cout<<"-1\n";return;}
	cout<<sum/2<<endl;
	for(int i=1; i<=sum/2; ++i){
		pii v=*s.rbegin();
		s.erase(v);
		pii u=*s.rbegin();
		s.erase(u);
		cout<<"1 "<<u.Y<<' '<<v.Y<<endl;
		u.X--;
		v.X--;
		s.insert(v);
		s.insert(u);
	}
}
int main() {
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    //fre_open
    ll tt=1;
    //cin>>tt;
    while(tt--) solve();
}

Compilation message (stderr)

nicegift.cpp: In function 'void fre_open()':
nicegift.cpp:26:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   26 | void fre_open(){freopen("file.in","r",stdin);freopen("file.out","w",stdout);}
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
nicegift.cpp:26:53: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   26 | void fre_open(){freopen("file.in","r",stdin);freopen("file.out","w",stdout);}
      |                                              ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 0 / 11
• Subtask 3: 0 / 12
• Subtask 4: 0 / 19
• Subtask 5: 0 / 51