Submission #711409

#	Time	Username	Problem	Language	Result	Execution time	Memory
711409		Johann	Uplifting Excursion (BOI22_vault)	C++14	80 / 100	5041 ms	284492 KiB

vault

// tatsaechlich in echt falsch, wie 8.in zeigt
#include "bits/stdc++.h"
using namespace std;

typedef long long ll;
typedef pair<ll, ll> pii;
typedef vector<pii> vpii;
typedef vector<ll> vi;
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()

vi calcShifts(ll a)
{
    vi ans;
    ll i = 0;
    while ((1LL << i) <= a)
    {
        a -= (1LL << i);
        ans.push_back(i++);
    }
    while (i > 0)
        if ((1LL << --i) <= a)
            ans.push_back(i), a -= (1 << i);
    return ans;
}

vi dp;
ll center;
void calcDP(vi &A, ll M)
{
    ll an = accumulate(A.begin(), A.begin() + M, 0);
    ll ap = accumulate(A.begin() + M + 1, A.begin() + 2 * M + 1, 0);

    center = M * max(an, ap) + 1;
    dp.assign(2 * center + 1, -1);
    dp[center] = A[M];
    for (int foo = 0; foo < 2; ++foo)
    {
        reverse(all(A)), reverse(all(dp));
        for (ll m = 1; m <= M; ++m)
        {
            ll maxNum = A[m + M];
            vi shifts = calcShifts(maxNum);
            for (int i : shifts)
            {
                ll amount = (1 << i);
                ll d = amount * m;
                for (int j = sz(dp) - 1; j >= d; --j)
                    dp[j] = max(dp[j], (dp[j - d] != -1) ? dp[j - d] + amount : -1);
            }
        }
    }
}

pii calcPref(vi &A, int M, ll L, ll &pref, ll &tmpans) // find last Prefix position { i, idx } with pref <= L, or { sz(A)-1 = 2 * M, A[2 * M] }
{
    int i = 0;
    tmpans = 0, pref = 0;
    for (; i < M; ++i)
        tmpans += A[i], pref += A[i] * (i - M);
    if (pref >= L)
        return {i, 0};
    while (i < sz(A) && pref + A[i] * (i - M) < L)
    {
        pref += A[i] * (i - M);
        tmpans += A[i];
        ++i;
    }
    if (i == sz(A))
        return {i - 1, A[i - 1]};

    ll delta = L - pref;
    assert(delta >= 0); // The expectation after the while loop is, that one is able to forfill this shit with the A[i] * (i - M) stuff
    ll l = delta / (i - M);
    pref += l * (i - M);
    tmpans += l;

    return {i, l};
}

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

    ll M, L;
    cin >> M >> L;
    vi A(2 * M + 1);
    for (int i = 0; i < sz(A); ++i)
        cin >> A[i];

    vi B(sz(A), 0);
    for (int i = 0; i < sz(B); ++i)
    {
        if (i == M)
        {
            B[i] = A[i];
            A[i] = 0;
            continue;
        }
        B[i] = min(M - 1, A[i]);
        A[i] -= B[i];
    }

    // Calc dp with normal stuff
    calcDP(B, M);

    ll ans = -1;
    for (int foo = 0; foo < 2; ++foo)
    {
        reverse(all(dp)), reverse(all(A));
        L = -L;

        ll i, idx, pref, tmpans;
        tie(i, idx) = calcPref(A, M, L - center, pref, tmpans);

        while (i < sz(A) && L - pref + center >= 0)
        {
            if (L - pref + center < sz(dp) && dp[L - pref + center] != -1)
                ans = max(ans, tmpans + dp[L - pref + center]);
            if (idx < A[i])
            {
                ++idx;
                ++tmpans;
                pref += i - M;
            }
            else
            {
                ++i;
                idx = 0;
            }
        }
    }

    if (ans == -1)
        cout << "impossible\n";
    else
        cout << ans << "\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: 0 / 10
• Subtask 6-2: 0 / 10