Submission #1101214

#	Time	Username	Problem	Language	Result	Execution time	Memory
1101214		andrei_iorgulescu	Boarding Passes (BOI22_passes)	C++14	100 / 100	363 ms	107116 KiB

passes

#include <bits/stdc++.h>

using namespace std;

#define int long long

using ld = long double;

ld inf = 1e12;

int n, g;
char a[100005];
int v[100005];
string ssss;
vector<int> pos[20];
int p[20][20][100005], s[20][20][100005];
int sp[100005];

ld dp[50005];

ld f(int b, int mask, int x)
{
    ld ans = dp[mask - (1 << b)];
    ld xxx = x;
    ans += ((xxx * (xxx - 1)) / 4.0d);
    ld xx = pos[b].size() - x;
    ans += ((xx * (xx - 1)) / 4.0d);
    //cout << b << ' ' << mask << ' ' << x << ' ';
    for (int b1 = 0; b1 < g; b1++)
    {
        if (b1 != b and ((1 << b1) & mask))
        {
            ans += p[b][b1][x];
            ans += s[b][b1][pos[b].size() - x];
        }
    }
    //cout << ans << endl;
    return ans;
}

signed main()
{
    cin >> ssss;
    n = ssss.size();
    for (int i = 1; i <= n; i++)
        a[i] = ssss[i - 1];
    for (int i = 1; i <= n; i++)
        v[i] = a[i] - 'A', g = max(g, v[i] + 1);
    for (int i = 1; i <= n; i++)
        pos[v[i]].push_back(i);
    for (int i = 0; i < g; i++)
    {
        for (int j = 0; j < g; j++)
        {
            if (i == j)
                continue;
            for (int q = 1; q <= n; q++)
            {
                sp[q] = sp[q - 1];
                if (v[q] == j)
                    sp[q]++;
            }
            for (int q = 0; q <= pos[i].size(); q++)
            {
                int sm = 0;
                if (q > 1)
                    sm = p[i][j][q - 1];
                if (q != 0)
                    sm += sp[pos[i][q - 1]];
                p[i][j][q] = sm;
            }
            for (int q = 0; q <= pos[i].size(); q++)
            {
                int sm = 0;
                if (q > 1)
                    sm = s[i][j][q - 1];
                if (q != 0)
                    sm += (sp[n] - sp[pos[i][pos[i].size() - q]]);
                s[i][j][q] = sm;
            }
        }
    }
    for (int mask = 1; mask < (1 << g); mask++)
    {
        dp[mask] = inf;
        for (int b = 0; b < g; b++)
        {
            if (mask & (1 << b))
            {
                int st = 0, pas = 1 << 16;
                while (pas != 0)
                {
                    if (st + pas + 1 <= pos[b].size() and f(b, mask, st + pas) >= f(b, mask, st + pas + 1))
                        st += pas;
                    pas /= 2;
                }
                for (int dlt = -2; dlt <= 2; dlt++)
                    if (st + dlt >= 0 and st + dlt <= pos[b].size())
                        dp[mask] = min(dp[mask], f(b, mask, st + dlt));
            }
        }
    }
    cout << setprecision(5) << fixed;
    cout << dp[(1 << g) - 1];
    return 0;
}

Compilation message (stderr)

passes.cpp: In function 'int main()':
passes.cpp:63:31: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   63 |             for (int q = 0; q <= pos[i].size(); q++)
      |                             ~~^~~~~~~~~~~~~~~~
passes.cpp:72:31: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |             for (int q = 0; q <= pos[i].size(); q++)
      |                             ~~^~~~~~~~~~~~~~~~
passes.cpp:93:38: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   93 |                     if (st + pas + 1 <= pos[b].size() and f(b, mask, st + pas) >= f(b, mask, st + pas + 1))
      |                         ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~
passes.cpp:98:52: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   98 |                     if (st + dlt >= 0 and st + dlt <= pos[b].size())
      |                                           ~~~~~~~~~^~~~~~~~~~~~~~~~

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