Submission #1309856

#	Time	Username	Problem	Language	Result	Execution time	Memory
1309856		shirokito	Detecting Molecules (IOI16_molecules)	C++20	69 / 100	201 ms	6184 KiB

molecules

#include <bits/stdc++.h>
using namespace std;

#define all(a) (a).begin(), (a).end()

using ll = long long;

const int N = 5e5 + 5;

mt19937 rng(363636);

pair<int, int> v[N];

namespace sub5 {
    bool check(int n, int l, int u) {
        return (n <= 10000 && u <= 500000);
    }

    bitset<N> dp;

    vector<int> find_subset(int l, int u, vector<int> w) {
        int n = w.size();

        dp[0] = 1;
        for (int &x: w) {
            dp |= (dp << x);
        }

        int cand_weight = -1;

        for (int x = l; x <= u; x++) {
            if (dp[x] == 1) {
                cand_weight = x;
                break;
            }
        }

        if (cand_weight == -1) {
            return vector<int> {};
        }

        vector<pair<int, int>> v;

        for (int i = 0; i < n; i++) {
            v.push_back({w[i], i});
        }

        for (int _ = 0; _ <= 100; _++) {

            shuffle(all(v), rng);

            vector<int> ans;

            int cur = cand_weight;

            for (int i = 0; i < n; i++) {
                if (cur - v[i].first >= 0 && dp[cur - v[i].first]) {
                    ans.push_back(v[i].second);
                    cur -= v[i].first;
                }
            }

            if (cur == 0) return ans;
        }
        
        return vector<int> {}; 
    }
}

namespace sub6 {
    pair<int, int> v[N];

    vector<int> find_subset(int l, int u, vector<int> w) {
        int n = w.size();

        for (int i = 0; i < n; i++) {
            v[i] = {w[i], i};
        }

        sort(v, v + n);

        if (v[0].first >= l && v[0].first <= u) {
            return vector<int> {0};
        }

        if (v[n - 1].first >= l && v[n - 1].first <= u) {
            return vector<int> {n - 1};
        }

        if (v[0].first > u) {
            return vector<int> {};
        }

        int B = (n <= 2000 ? n : sqrtl(n));

        for (int _ = 0; _ <= 100; _++) {
            for (int L = 0; L < n; L += B) {
                int R = min(n - 1, L + B - 1);
                shuffle(v + L, v + R + 1, rng);
            }

            vector<int> ans;
            ll cur = 0;

            for (int i = 0; i < n; i++) {
                cur += v[i].first;
                ans.push_back(v[i].second);

                if (cur >= l && cur <= u) {
                    return ans;
                }
            }   
        }

        return vector<int> {};
    }
};

vector<int> find_subset(int l, int u, vector<int> w) {
    int n = w.size();
    if (sub5::check(n, l, u)) return sub5::find_subset(l, u, w);
    return sub6::find_subset(l, u, w);
}

#ifdef LOCAL

void solve() {
    int n, l, u; cin >> n >> l >> u;
    vector<int> w(n); for (int &x: w) cin >> x;

    auto ans = find_subset(l, u, w);

    for (int x: ans) cout << x << ' ';
    cout << '\n';
}

signed main() {
    cin.tie(0) -> sync_with_stdio(0);

    int T = 1; // cin >> T;
    while (T--) {
        solve();
    }
}

#endif

Compilation message (stderr)

molecules.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~
molecules_c.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~

• Subtask 1: 9 / 9
• Subtask 2: 10 / 10
• Subtask 3: 12 / 12
• Subtask 4: 15 / 15
• Subtask 5: 23 / 23
• Subtask 6: 0 / 31