Submission #949774

#	Time	Username	Problem	Language	Result	Execution time	Memory
949774		sysia	Boarding Passes (BOI22_passes)	C++17	60 / 100	2040 ms	31988 KiB

passes

//Sylwia Sapkowska
#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;

void __print(int x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << "'" << x << "'";}
void __print(const char *x) {cerr << '"' << x << '"';}
void __print(const string &x) {cerr << '"' << x << '"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef LOCAL
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif

#define int long long
typedef pair<int, int> T;
const int oo = 1e18, oo2 = 1e9+7, K = 30;
const int mod = 998244353;
typedef long double ld;

void solve(){
    string s; cin >> s;
    int n = (int)s.size();
    vector<int>used(K);
    for (auto c: s) used[c-'A']++;
    vector<int>scale(K);
    int G = 0;
    for (int i = 0; i<K; i++) if (used[i]) scale[i] = G++;
    debug(G); //grupy [0, G-1]
    vector<vector<int>>what(G);
    for (int i = 0; i<n; i++) {
        what[scale[s[i]-'A']].emplace_back(i);
    }
    vector<ld>dp((1<<G), oo);
    dp[0] = 0;
    vector left(n, vector<int>(G)), right(n, vector<int>(G)); //dla i-tego indeksu grupa g doklada left[i] elementow z lewej
    for (int i = 0; i<n; i++){
        for (int g = 0; g < G; g++){
            if (scale[s[i]-'A'] == g) continue;
            int t = (int)(lower_bound(what[g].begin(), what[g].end(), i)-what[g].begin());
            left[i][g] = t;
            right[i][g] = (int)what[g].size()-t;
        }
    }
    for (int mask = 0; mask < (1<<G); mask++){
        debug(mask, dp[mask]);
        for (int i = 0; i<G; i++){
            if (mask&(1<<i)) continue;
            debug(mask, i);
            //dokladam grupe i --> to sie wydarzy 2^{G-1} razy
            int k = (int)what[i].size();
            long double curr = 0;
            for (int rep = 0; rep < k; rep++){ //kGlog n
                ld L = (ld)rep/2.0;
                ld R = (k-rep-1)/2.0;
                for (int t = 0; t < G; t++){
                    if (mask&(1<<t)){
                        L += left[what[i][rep]][t];
                        R += right[what[i][rep]][t];
                    }
                }
                debug(L, R);
                curr += min(L, R);
            }
            dp[mask^(1<<i)] = min(dp[mask^(1<<i)], dp[mask] + curr);
        }
    }
    cout << fixed << setprecision(10) << dp.back() << "\n";
}

int32_t main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int t = 1;
    //cin >> t;
    while (t--) solve();

    return 0;
}

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