Submission #721817

#	Time	Username	Problem	Language	Result	Execution time	Memory
721817		dxz05	Uplifting Excursion (BOI22_vault)	C++17	0 / 100	549 ms	524288 KiB

vault

#pragma GCC optimize("Ofast,O3,unroll-loops")

#include <bits/stdc++.h>

using namespace std;

mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());

typedef long long ll;
#define all(x) (x).begin(), (x).end()
#define MP make_pair
const int N = 100500;

long long stress(int m, ll L, vector<ll> a){
    vector<int> b;
    for (int i = 0; i <= m; i++){
        while (a[i]--) b.push_back(i);
    }

    int LIM = accumulate(all(b), 0) + 1;


    if (L >= LIM) return -1;

    vector<int> dp(LIM, -1e9);
    dp[0] = 0;

    for (int x : b) {
        for (int i = LIM - 1; i >= x; i--) {
            dp[i] = max(dp[i], dp[i - x] + 1);
        }
    }

    return dp[L] < 0 ? -1 : dp[L];
}

long long solve(int m, ll L, vector<ll> a){
    if (L < 0) return -1;

    if (L == 0) return a[0];

    ll ans = -1;

    ll tot = 0, cnt = a[0];

    vector<int> dp(1, 0);
    for (int v = 1; v <= m; v++){
        assert(tot <= L);

        ll x = min(a[v], (L - tot) / v);
        tot += x * v;
        cnt += x;

        if (tot == L){
            ans = max(ans, cnt);
        } else if (a[v] > x){
            int add = 0;
            for (ll del = tot + v - L; del < dp.size(); del += v){
                add++;
                if (add <= a[v] - x) ans = max(ans, cnt - dp[del] + add);
            }
        }

        for (int it = 0; it < min(3LL * m / v, x); it++){
            dp.resize(dp.size() + v, 1e9);
            for (int i = dp.size() - 1; i >= v; i--){
                dp[i] = min(dp[i], dp[i - v] + 1);
            }
        }
    }

    return ans;
}

int main() {
    ios_base::sync_with_stdio(false);

#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

/*
    int iterations = 1000;
    while (iterations--){
        int m = rng() % 10 + 1;
        vector<ll> a(m + 1);
        for (int i = 0; i <= m; i++){
            a[i] = rng() % 10 + 1;
        }

        for (int L = 0; L <= 100; L++) {
            long long correct = stress(m, L, a);
            long long result = solve(m, L, a);
            if (result != correct){
                cout << correct << ' ' << result << endl << endl;
                cout << m << ' ' << L << endl;
                for (int i = 0; i <= m; i++) cout << a[i] << ' ';
                cout << endl;
                exit(0);
            }
        }

    }
    cout << "Accepted" << endl;
    exit(0);
*/

    int m; ll L;
    cin >> m >> L;

    vector<ll> a(m + 1);
    for (int i = -m; i <= m; i++){
        cin >> a[abs(i)];
    }

    long long correct = stress(m, L, a);

    long long result = solve(m, L, a);


    if (result != -1){
        cout << result << endl;
    } else {
        cout << "impossible" << endl;
    }

    return 0;
}

Compilation message (stderr)

vault.cpp: In function 'long long int solve(int, ll, std::vector<long long int>)':
vault.cpp:58:44: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |             for (ll del = tot + v - L; del < dp.size(); del += v){
      |                                        ~~~~^~~~~~~~~~~
vault.cpp: In function 'int main()':
vault.cpp:117:15: warning: unused variable 'correct' [-Wunused-variable]
  117 |     long long correct = stress(m, L, a);
      |               ^~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 15
• Subtask 3-1: 0 / 10
• Subtask 3-2: 0 / 10
• Subtask 4-1: 0 / 10
• Subtask 4-2: 0 / 10
• Subtask 5-1: 0 / 10
• Subtask 5-2: 0 / 10
• Subtask 6-1: 0 / 10
• Subtask 6-2: 0 / 10