Submission #580156

#	Time	Username	Problem	Language	Result	Execution time	Memory
580156		Elias	Boarding Passes (BOI22_passes)	C++17	0 / 100	1 ms	340 KiB

passes

#include <bits/stdc++.h>

#ifndef _DEBUG
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#endif

using namespace std;

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

    string s;
    cin >> s;

    int n = s.size();
    int g = *max_element(s.begin(), s.end()) - 'A' + 1;

    vector<int> a(n);
    vector<vector<int>> pos(g);

    for (int i = 0; i < n; i++)
        pos[a[i] = s[i] - 'A'].push_back(i);

    vector<vector<int>> prefix(g, vector<int>(n));
    vector<vector<int>> suffix(g, vector<int>(n));

    for (int k = 0; k < g; k++)
    {
        for (int i = 1; i < n; i++)
            prefix[k][i] = prefix[k][i - 1] + bool(a[i - 1] == k);
        for (int i = n - 2; i >= 0; i--)
            suffix[k][i] = suffix[k][i + 1] + bool(a[i + 1] == k);
    }

    vector<double> dp(1 << g, 1e20);
    dp[0] = 0;

    vector<vector<int>> preSum(g, vector<int>(g));
    vector<vector<int>> sufSum(g, vector<int>(g));

    for (int i = 0; i < g; i++)
    {
        for (int j = 0; j < g; j++)
        {
            int pre = 0;
            int suf = 0;

            for (int p : pos[i])
                pre += prefix[j][p], suf += suffix[j][p];

            preSum[i][j] = pre;
            sufSum[i][j] = suf;
        }
    }

    for (int b = 1; b < 1 << g; b++)
    {
        for (int i = 0; i < g; i++)
        {
            if (!(b & (1 << i)))
                continue;

            double cost = 0;

            int pre = 0;
            int suf = 0;

            for (int j = 0; j < g; j++)
            {
                if (i != j && (b & j))
                {
                    pre += preSum[i][j];
                    suf += sufSum[i][j];
                }
            }

            cost += min(pre + 0.5 * preSum[i][i], suf + 0.5 * sufSum[i][i]);

            dp[b] = min(dp[b], dp[b ^ (1 << i)] + cost);
        }
    }

    cout << setprecision(15) << dp.back();
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 25
• Subtask 3: 0 / 30
• Subtask 4: 0 / 40