Submission #646334

#	Time	Username	Problem	Language	Result	Execution time	Memory
646334		dooompy	Boarding Passes (BOI22_passes)	C++17	5 / 100	3 ms	1556 KiB

passes

#include "bits/stdc++.h"

using namespace std;

void abc() {cout << endl;}
template <typename T, typename ...U> void abc(T a, U ...b) {
    cout << a << ' ', abc(b...);
}
template <typename T> void printv(T l, T r) {
    while (l != r) cout << *l << " \n"[++l == r];
}
template <typename A, typename B> istream& operator >> (istream& o, pair<A, B> &a) {
    return o >> a.first >> a.second;
}
template <typename A, typename B> ostream& operator << (ostream& o, pair<A, B> a) {
    return o << '(' << a.first << ", " << a.second << ')';
}
template <typename T> ostream& operator << (ostream& o, vector<T> a) {
    bool is = false;
    for (T i : a) {o << (is ? ' ' : '{'), is = true, o << i;}
    return o << '}';
}

#ifdef local
#define test(args...) abc("[" + string(#args) + "]", args)
#else
#define test(args...) void(0)
#endif

using ll = long long;

int converted[100005];
int idx = 0;

long double fromleft[16][16][100005];
long double fromright[16][16][100005];
vector<vector<int>> groups;
int g;

long double calc(int amt) {
    return (long double) ((long double) amt * (long double) (amt-1.0)) / 4.0;
}

long double getans(int mask, int j, int k) {
    if (k >= groups[j].size()) return 1e15;

    long double val = calc(k + 1) + calc((int) groups[j].size() - k - 1);

    for (int i = 0; i < g; i++) {
        if ((1 << i) & mask) {
            val += fromleft[j][i][groups[j][k]];

            if (k + 1 == groups[j].size()) continue;
            val += fromright[j][i][groups[j][k+1]];
        }
    }

    return val;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
//    freopen("", "r", stdin);
//    freopen("", "w", stdout);

    string s; cin >> s;
    int n = s.size();

    set<char> dup;
    map<char, int> m;

    for (int i = 0; i < n; i++) {
        if (m.count(s[i]) != 0) {
            converted[i] = m[s[i]];
        } else {
            m[s[i]] = m.size();
            converted[i] = m[s[i]];
        }
    }

    g = m.size();

    groups.resize(g);

    for (int i = 0; i < n; i++) {
        groups[converted[i]].push_back(i);
    }

    for (int l = 0; l < g; l++) {
        for (int r = 0; r < g; r++) {

            long double ct = 0, res = 0;

            for (int i = 0; i < n; i++) {
                if (converted[i] == l) {
                    ct++;
                } else if (converted[i] == r) {
                    res += ct;
                    fromleft[r][l][i] = res;
                }
            }

            ct = 0, res = 0;

            for (int i = n - 1; i >= 0 ; i--) {
                if (converted[i] == l) {
                    ct++;
                } else if (converted[i] == r) {
                    res += ct;
                    fromright[r][l][i] = res;
                }
            }
        }
    }

    vector<long double> dp(1 << g, 1e15);

    dp[0] = 0;

    for (int mask = 0; mask < (1 << g); mask++) {
        for (int j = 0; j < g; j++) {
            if (!((1 << j) & mask)) {
                long double cur = calc(groups[j].size());

                long double temp = 0;

                for (int i = 0; i < g; i++) {
                    if ((1 << i) & mask) {
                        temp += fromright[j][i][groups[j][0]];
                    }
                }

                long double temp1 = 0;

                for (int i = 0; i < g; i++) {
                    if ((1 << i) & mask) {
                        temp += fromleft[j][i][groups[j].back()];
                    }
                }

                cur += min(temp, temp1);

                int l = 0, r = groups[j].size() - 1;

                while (r - l > 2) {
                    int m1 = l + (r - l) / 3, m2 = r - (r - l) / 3;

                    long double val1 = getans(mask, j, m1), val2 = getans(mask, j, m2);

                    if (val1 < val2) {
                        r = m2;
                    } else {
                        l = m1;
                    }

                }

                cur = min({cur, getans(mask, j, l), getans(mask, j, l+1), getans(mask, j, l+2)});

                dp[mask | (1 << j)] = min(dp[mask | (1 << j)], dp[mask] + cur);
            }
        }
    }

    cout << setprecision(30) << fixed << dp[(1 << g) - 1];
}

Compilation message (stderr)

passes.cpp: In function 'long double getans(int, int, int)':
passes.cpp:45:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   45 |     if (k >= groups[j].size()) return 1e15;
      |         ~~^~~~~~~~~~~~~~~~~~~
passes.cpp:53:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |             if (k + 1 == groups[j].size()) continue;
      |                 ~~~~~~^~~~~~~~~~~~~~~~~~~

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