Submission #574134

#	Time	Username	Problem	Language	Result	Execution time	Memory
574134		eecs	Boarding Passes (BOI22_passes)	C++17	0 / 100	364 ms	292 KiB

passes

#include <bits/stdc++.h>
using namespace std;

const int n = 7;
string str;
long long f[1 << n];

int main() {
    ios::sync_with_stdio(0), cin.tie(0);
    cin >> str;
    fill(f + 1, f + (1 << n), 1e18);
    for (int S = 0; S < 1 << n; S++) {
        for (int i = 0; i < n; i++) if (!(S >> i & 1)) {
            auto calc = [&](int p) {
                int c0 = 0, c1 = 0;
                long long s = 0;
                for (int j = p; ~j; j--) {
                    if (str[j] - 'A' == i) c0++;
                    else if (S >> (str[j] - 'A') & 1) s += c0;
                }
                for (int j = p + 1; j < str.size(); j++) {
                    if (str[j] - 'A' == i) c1++;
                    else if (S >> (str[j] - 'A') & 1) s += c1;
                }
                return 2 * s + 1LL * c0 * (c0 - 1) / 2 + 1LL * c1 * (c1 - 1) / 2;
            };
            for (int p = -1; p < (int)str.size(); p++) {
                f[S | (1 << i)] = min(f[S | (1 << i)], f[S] + calc(p));
            }
        }
    }
    cout << f[(1 << n) - 1] / 2 << "." << (f[(1 << n) - 1] % 2 ? 5 : 0) << "\n";
    return 0;
}

Compilation message (stderr)

passes.cpp: In lambda function:
passes.cpp:21:39: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |                 for (int j = p + 1; j < str.size(); j++) {
      |                                     ~~^~~~~~~~~~~~

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