Submission #495259

#	Time	Username	Problem	Language	Result	Execution time	Memory
495259		armashka	Gift (IZhO18_nicegift)	C++17	0 / 100	9 ms	204 KiB

nicegift

#include <bits/stdc++.h>
 
//#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
 
#define fast ios_base::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
#define all(v) v.begin(),v.end()
#define pb push_back
#define sz size()
#define ft first
#define sd second
 
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef unsigned long long ull;
 
const int N = 1e6 + 5;
const ll M = 1e8;
const ll inf = 1e9;
const ll mod = 1e9;
const double Pi = acos(-1); 
 
ll binpow(ll x, ll ti) { ll res = 1;while (ti){if(ti & 1)res *= x;x *= x;ti >>= 1; x %= mod; res %= mod;} return res;}
ll binmul(ll x, ll ti) { ll res = 0;while (ti){if(ti & 1)res += x;x += x;ti >>= 1; x %= mod; res %= mod;} return res;}
ll nok(ll a, ll b) { return (a*b)/__gcd(abs(a),abs(b)) * (a*b > 0 ? 1 : -1); }
bool odd(ll n) { return (n % 2 == 1); }
bool even(ll n) { return (n % 2 == 0); }            
                                                                    
int n, k, a[N], sum;
vector <pair<pair<int, int>, int>> ans;
 
const void solve(/*Armashka*/) {
	cin >> n >> k;
	for (int i = 1; i <= n; ++ i) cin >> a[i];
	while (1) {
		bool ok = 0;
		vector <ll> e, o;
		sum = 0;
		for (int i = 1; i <= n; ++ i) {
			if (a[i] == 0) continue;
			ok = 1;
			sum += a[i];
			if (even(a[i])) e.pb(i);
			else o.pb(i);
		}
		if (!ok) break;
		if (even(sum)) {
			if (e.sz > 1) { -- a[e[0]], -- a[e[1]]; ans.pb({{e[0], e[1]}, 1});  continue; }
			else if (o.sz > 1) { -- a[o[0]], -- a[o[1]]; ans.pb({{o[0], o[1]}, 1});  continue; }
			else { 
				if (e.sz && o.sz) {
					-- a[e[0]], -- a[o[0]];
					ans.pb({{e[0], o[0]}, 1});
				} else {
					cout << "-1\n";
					return;
				}
			}
		} else {
			if (e.sz && o.sz) {
				-- a[e[0]], -- a[o[0]];
				ans.pb({{e[0], o[0]}, 1});
			} else {
				cout << "-1\n";
				return;
			}
		}
	}
	cout << ans.sz << "\n";
	for (auto x : ans) cout << x.sd << " " << x.ft.ft << " " << x.ft.sd << "\n";
}
 
signed main() {
    fast;
	//freopen("divide.in", "r", stdin);
	//freopen("divide.out", "w", stdout);
    int tt = 1;
    //cin >> tt;
    while (tt --) {
    	solve();
	}
}
 
/*
 
6 8
3 3 3 3
1 2 1 2
3 4 3 4
5 5 5 5
4 3 4 3
4 4 4 4
2 1 2 1
3 6 3 6
 
*/
 
/*
9 12
1 9 4
1 2 5
2 3 7
2 4 3
4 3 6
3 6 4
8 7 10
6 7 5
5 8 1
9 5 7
5 4 12
6 8 2
2
4 7
5
1 6
5 3
4 8
5 8
1 5
 
*/

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