Submission #911950

#	Time	Username	Problem	Language	Result	Execution time	Memory
911950		GrindMachine	Gift (IZhO18_nicegift)	C++17	100 / 100	1247 ms	97952 KiB

nicegift

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*

refs:
https://oj.uz/submission/908159

*/

const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

void solve(int test_case)
{
    ll n,k; cin >> n >> k;
    vector<ll> a(n+5);
    rep1(i,n) cin >> a[i];
 
    ll sum = 0;
    rep1(i,n) sum += a[i];
 
    if(sum%k){
        cout << -1 << endl;
        return;
    }
 
    ll mx = *max_element(all(a));
    if(mx > sum/k){
        cout << -1 << endl;
        return;
    }
 
    priority_queue<pll> pq;
    rep1(i,n) pq.push({a[i],i});
 
    vector<vector<ll>> ans;
 
    while(true){        
        if(!pq.top().ff) break;

        vector<ll> curr;
        curr.pb(0);
        
        rep1(iter,k){
            auto [val,i] = pq.top();
            pq.pop();
            curr.pb(i);
        }

        ll curr_mx = a[curr[1]];
        ll curr_mn = a[curr.back()];

        ll remain_mx = -inf2;
        if(!pq.empty()){
            remain_mx = pq.top().ff;
        }

        // what is the max val that can be subtracted?
        ll l = 1, r = curr_mn;
        ll mx_sub = -1;

        while(l <= r){
            ll mid = (l+r) >> 1;
            ll new_sum = sum-mid*k;
            if(curr_mx-mid <= new_sum/k and remain_mx <= new_sum/k){
                mx_sub = mid;
                l = mid+1;
            }
            else{
                r = mid-1;
            }
        }

        assert(mx_sub != -1);

        curr[0] = mx_sub;
        sum -= mx_sub*k;

        rep1(ind,sz(curr)-1){
            ll i = curr[ind];
            a[i] -= mx_sub;
            pq.push({a[i],i});
        }

        ans.pb(curr);
    }
    
    assert(sum == 0);
    rep1(i,n){
        assert(a[i] == 0);
    }
 
    cout << sz(ans) << endl;
    trav(ar,ans){
        trav(i,ar) cout << i << " ";
        cout << endl;
    }
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

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