Submission #927508

#	Time	Username	Problem	Language	Result	Execution time	Memory
927508		math_rabbit_1028	Uplifting Excursion (BOI22_vault)	C++14	100 / 100	3615 ms	2220 KiB

vault

#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
typedef pair<int, int> pii;
typedef long long ll;

int M, K;
ll L, S, arr[1010], rem[1010], ans;

int dp[2][202020];

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    cin >> M >> L; K = 2*M*M;
    for (int i = 0; i <= 2*M; i++) cin >> arr[i];
    for (int i = 0; i <= 2*M; i++) S += (i-M)*arr[i];
    if (S < L) {
        L = -L;
        for (int i = 0; i <= M; i++) swap(arr[i], arr[2*M-i]);
    }

    S = 0;
    for (int i = 0; i <= M; i++) {
        S += (i-M)*arr[i];
        ans += arr[i];
        rem[2*M-i] = arr[i];
        arr[i] = 0;
    }
    if (S > L) {
        cout << "impossible\n";
        return 0;
    }
    for (int i = M+1; i <= 2*M; i++) {
        ll t = (L-S)/(i-M);
        if (t >= arr[i]) {
            ans += arr[i];
            rem[2*M-i] = arr[i];
            S += arr[i]*(i-M);
            arr[i] = 0;
        }
        else {
            ans += t;
            rem[2*M-i] = t;
            S += t*(i-M);
            arr[i] -= t;
            break;
        }
    }

    for (int j = 0; j <= K; j++) dp[0][j] = -1e9;
    dp[0][M*M] = 0;
    for (int i = 1; i <= M; i++) {
        for (int r = 0; r < i; r++) {
            deque< pair<int, int> > dq1, dq2;
            for (int j = r; j <= K; j += i) {
                while (dq1.size() > 0 && (j-dq1.front().fi)/i > arr[M+i]) dq1.pop_front();
                while (dq1.size() > 0 && dq1.back().se + (j-dq1.back().fi)/i <= dp[0][j]) dq1.pop_back();
                dq1.push_back({j, dp[0][j]});
                while (dq2.size() > 0 && (j-dq2.front().fi)/i > rem[M+i]) dq2.pop_front();
                while (dq2.size() > 0 && dq2.back().se - (j-dq2.back().fi)/i <= dp[0][j]) dq2.pop_back();
                dq2.push_back({j, dp[0][j]});
                dp[1][j] = max(dq1.front().se + (j-dq1.front().fi)/i, dq2.front().se - (j-dq2.front().fi)/i);
            }
        }
        for (int j = 0; j <= K; j++) dp[0][j] = dp[1][j];
    }
    for (int i = M+1; i <= 2*M; i++) {
        for (int r = 0; r < i-M; r++) {
            deque< pair<int, int> > dq;
            int j = r; 
            while (j+i-M <= K) j += i-M;
            for (; j >= r; j -= i-M) {
                while (dq.size() > 0 && (dq.front().fi-j)/(i-M) > arr[2*M-i]) dq.pop_front();
                while (dq.size() > 0 && dq.back().se + (dq.back().fi-j)/(i-M) <= dp[0][j]) dq.pop_back();
                dq.push_back({j, dp[0][j]});
                dp[1][j] = dq.front().se + (dq.front().fi-j)/(i-M);
            }
        }
        for (int r = 0; r < i-M; r++) {
            deque< pair<int, int> > dq;
            int j = r; 
            while (j+i-M <= K) j += i-M;
            for (; j >= r; j -= i-M) {
                while (dq.size() > 0 && (dq.front().fi-j)/(i-M) > rem[2*M-i]) dq.pop_front();
                while (dq.size() > 0 && dq.back().se - (dq.back().fi-j)/(i-M) <= dp[0][j]) dq.pop_back();
                dq.push_back({j, dp[0][j]});
                dp[1][j] = max(dp[1][j], dq.front().se - (dq.front().fi-j)/(i-M));
            }
        }
        for (int j = 0; j <= K; j++) dp[0][j] = dp[1][j];
    }

    if (dp[0][L-S+M*M] <= -1e8) cout << "impossible\n";
    else cout << ans + dp[0][L-S+M*M] << "\n";

    return 0;
}

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