Submission #495230

#	Time	Username	Problem	Language	Result	Execution time	Memory
495230		pragmatist	Gift (IZhO18_nicegift)	C++14	18 / 100	130 ms	43300 KiB

nicegift

#include <bits/stdc++.h>                            
 
#define pb push_back
#define sz(v) (int)v.size()
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
#define x first
#define y second
#define int long long
#define nl "\n"
 
using namespace std;

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

const int N = (int)3e5 + 7;
const int M = (int)7e6 + 7;
const ll MOD = (ll)1e9 + 7;                    
const int inf = (int)1e9 + 7;
const ll INF = (ll)3e18 + 7;

pii dir[] = {{-1, -1}, {1, 1}, {-1, 1}, {1, -1}};

int n, k, a[N];

void solve() {          	             
	cin >> n >> k;
	int sum = 0, mx = 0;
	set<pii> s;
	for(int i = 1; i <= n; ++i) {
		cin >> a[i];
		mx = max(mx, a[i]);
		sum += a[i];
		s.insert({a[i], i});
	}
	sort(a + 1, a + 1 + n);
	if(sum % k || mx > sum - mx) cout << "-1\n", exit(0);
	cout << sum / 2 << nl;
	for(int i = 1; i <= sum / 2; ++i) {
		pii x = *s.rbegin();
		s.erase(x);
		pii y = *s.rbegin();
		s.erase(y);
		cout << "1 " << x.y << ' ' << y.y << nl;
		x.x--;
		y.x--;
		s.insert(x);
		s.insert(y);
	}
}

signed main() {                   
	ios_base::sync_with_stdio(NULL);
    cin.tie(0);
    cout.tie(0);
   	int test = 1;
	//cin >> test;
	for(int i = 1; i <= test; ++i) {
        //cout << "Case " << i << ": ";
        solve();
    }
    return 0;
}

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