Submission #1067438

#	Time	Username	Problem	Language	Result	Execution time	Memory
1067438		Whisper	Let's Win the Election (JOI22_ho_t3)	C++17	100 / 100	203 ms	4444 KiB

Main

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

#define int long long
#define FOR(i, a, b) for (int i = (a); i <= (b); i++)
#define FORD(i, a, b) for (int i = (b); i >= (a); i --)
#define REP(i, a) for (int i = 0; i < (a); ++i)
#define REPD(i, a) for (int i = (a) - 1; i >= 0; --i)

#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)


constexpr ll LINF = (1ll << 60);
constexpr int INF = (1ll << 30);
constexpr int Mod = 1e9 + 7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

/*
    Phu Trong from Nguyen Tat Thanh High School for gifted student
*/

template <class X, class Y>
    bool minimize(X &x, const Y &y){
        X eps = 1e-9;
        if (x > y + eps) {x = y; return 1;}
        return 0;
    }

template <class X, class Y>
    bool maximize(X &x, const Y &y){
        X eps = 1e-9;
        if (x + eps < y) {x = y; return 1;}
        return 0;
    }
#define MAX                 505
int N, K;
double A[MAX], B[MAX];

double dp[MAX][MAX], cost[MAX][MAX];
void process(void){
    cin >> N >> K;
    for (int i = 1; i <= N; ++i){
        cin >> A[i] >> B[i];
        if(B[i] == -1) B[i] = 1e9;
    }
    vector<int> order(N + 1);
    iota(order.begin(), order.end(), 0);

    sort(order.begin() + 1, order.end(), [&](int i, int j){
        return B[i] < B[j];
    });

    vector<double> vals;
    FOR(i, 0, N) FOR(j, 0, N) cost[i][j] = 1e9;
    for (int i = N; i >= 1; --i){
        vals.push_back(A[order[i]]);
        sort(vals.begin(), vals.end());
        double sm = 0;
        cost[i][0] = 0;
        for (int j = 0; j < (int)vals.size(); ++j){
            sm += vals[j];
            cost[i][j + 1] = sm;
        }
    }
    double ans = cost[1][K];
    for (int tak = 0; tak <= K; ++tak){
        for (int i = 0; i <= K; ++i){
            for (int j = 0; j <= K; ++j){
                dp[i][j] = 1e9;
            }
        }
        dp[0][0] = 0;
        for (int i = 1; i <= K; ++i){
            for (int j = 0; j <= i; ++j){
                dp[i][j] = dp[i - 1][j] + (double)A[order[i]] / (double)(tak + 1);
                if(j > 0)
                    minimize(dp[i][j], dp[i - 1][j - 1] + (double)B[order[i]] / (double)(j));
                if(j == tak){
                    int need = K - i;
                    minimize(ans, dp[i][j] + (double)cost[i + 1][need] / (double)(tak + 1));
                }
            }
        }
    }
    cout << setprecision(10) << fixed << ans;
}
signed main(){
    #define name "Whisper"
    cin.tie(nullptr) -> sync_with_stdio(false);
    //freopen(name".inp", "r", stdin);
    //freopen(name".out", "w", stdout);
    process();
    return (0 ^ 0);
}

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 11 / 11
• Subtask 4: 12 / 12
• Subtask 5: 33 / 33
• Subtask 6: 11 / 11
• Subtask 7: 23 / 23