Submission #857724

#	Time	Username	Problem	Language	Result	Execution time	Memory
857724		vgtcross	Uplifting Excursion (BOI22_vault)	C++17	20 / 100	3801 ms	9812 KiB

vault

#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using pii = pair<int, int>;

const int N = 1100000;
int dp[N], nx[N];
ll dp2[N], nx2[N];

void solve() {
    int m;
    ll x;
    cin >> m >> x;
    vector<ll> a(2*m+1);
    ll maxa = 0;
    for (ll &i : a) {
        cin >> i;
        maxa = max(maxa, i);
    }
    
    if (maxa <= 100) {
        ll mins = 0, maxs = 0;
        vector<pii> v;
        for (int i = -m; i <= m; ++i) {
            int f = a[i+m];
            
            if (i < 0) mins += f * i;
            else maxs += f * i;
            
            int z = 1;
            while (f > z) {
                v.push_back({z * i, z});
                f -= z;
                z *= 2;
            }
            if (f > 0) v.push_back({f * i, f});
        }
        
        memset(dp, 0xc0, sizeof dp);
        memset(nx, 0xc0, sizeof nx);
        dp[0] = nx[0] = 0;
        for (pii p : v) {
            for (int i = -550000; i <= 550000; ++i) {
                int j = i + p.first;
                if (-550000 <= j && j <= 550000) nx[(j + N) % N] = max(nx[(j + N) % N], dp[(i + N) % N] + p.second);
            }
            copy(nx, nx+N, dp);
        }
        
        if (x < mins || x > maxs) cout << "impossible\n";
        else cout << (dp[(x + N) % N] < 0 ? "impossible" : to_string(dp[(x + N) % N])) << '\n';
    } else {
        ll maxs = 0;
        vector<pii> v;
        for (int i = 1; i <= m; ++i) {
            ll f = a[i+m];
            
            maxs += f * i;
            
            f = min(f, (ll) m-1);
            
            int z = 1;
            while (f > z) {
                v.push_back({z * i, z});
                f -= z;
                z *= 2;
            }
            if (f > 0) v.push_back({f * i, f});
        }
        
        ll ans = -1;
        ll ofs = 0;
        for (int k = 1; k <= m; ++k) {
            memset(dp2, 0xc0, 77000 * sizeof(ll));
            memset(nx2, 0xc0, 77000 * sizeof(ll));
            dp2[0] = nx2[0] = 0;
            for (pii p : v) {
                for (int i = 0; i <= 70000; ++i) {
                    int j = i + p.first;
                    if (j <= 70000) nx2[j] = max(nx2[j], dp2[i] + p.second);
                }
                copy(nx2, nx2+77000, dp2);
            }
            
            for (int i = 0; i <= 70000; ++i) {
                if (i + ofs > x) break;
                if ((x - i - ofs) % k == 0) ans = max(ans, dp[i] + (x - i - ofs) / k);
            }
            
            ofs += max(0ll, a[k+m] - m + 1) * k;
        }
        
        cout << (ans == -1 ? "impossible" : to_string(ans + a[m])) << '\n';
    }
}

int main() {
    cin.tie(0) -> sync_with_stdio(0);
    
    solve();
}

• Subtask 1: 5 / 5
• Subtask 2: 15 / 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