Submission #1033027

#	Time	Username	Problem	Language	Result	Execution time	Memory
1033027		phoenix	Gift (IZhO18_nicegift)	C++17	100 / 100	472 ms	124512 KiB

nicegift

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

const int M = (1 << 20);

int n, k;

ll total;
pair<ll, int> a[M];
vector<vector<ll>> res;

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> k;
    for (int i = 0; i < n; i++) {
        cin >> a[i].first;
        total += a[i].first;
        a[i].second = i + 1;
    }
    sort(a, a + n);
    if (total % k || a[n - 1].first > total / k) {
        cout << -1;
        return 0;
    }
    int l = 0, r = n - 1;
    while (l <= r) {
        ll X = min(a[l].first, (total - k * a[r].first) / k);
        if (X) {
            res.push_back({X});
            for (int i = l; i < l + k; i++) {
                a[i].first -= X;
                total -= X;
                res.back().push_back(a[i].second);
            }
            for (int i = r + 1; i < n; i++) {
                a[i].first -= X;
                res.back().push_back(a[i].second);
            }
        }
        if (a[r].first == total / k) {
            total -= a[r].first;
            r--, 
            k--;
        }
        while (l <= r && !a[l].first) l++;
    }
    if (a[n - 1].first) {
        res.push_back({a[n - 1].first});
        while (n && a[n - 1].first)
            res.back().push_back(a[--n].second);
    }
    cout << (int)res.size() << '\n';
    for (auto v : res) {
        for (ll c : v) cout << c << ' ';
        cout << '\n';
    }
}

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