Submission #871126

#	Time	Username	Problem	Language	Result	Execution time	Memory
871126		HorizonWest	Let's Win the Election (JOI22_ho_t3)	C++17	0 / 100	2578 ms	1002724 KiB

Main

#include <bits/stdc++.h>
using namespace std;
 
#define endl '\n'
#define db double
#define ll __int128
//#define int long long
#define pb push_back
#define fs first
#define sd second
#define Mod long(1e9 + 7)
#define all(x) x.begin(), x.end()
#define unvisited long(-1)
#define Eps double(1e-9)
#define _for(i, n) for(int i = 0; i < (n); i++)
#define dbg(x) cout << #x ": " << x << endl;
 
const int Max = 1e6 + 7, Inf = 1e9 + 7;
 
void print(bool x) { cout << (x ? "YES" : "NO") << endl; }
 
string tostring (__int128 x)
{
    string ans = "";
    while(x > 0)
    {
        ans += (x % 10 + '0');
        x /= 10;
    }
    reverse(all(ans));
    return ans;
}
 
void printdb(double ans, int k)
{
    cout << setiosflags(ios::fixed)
         << setiosflags(ios::showpoint)
         << setprecision(k) << ans << endl;
}

int n, m; vector <pair<db, db>> v;

double f(db l)
{
    vector <vector<vector<db>>> dp(n + 2, vector <vector<db>> (
        m + 2, vector <db> (m + 2, Inf)
    )); dp[0][1][0] = 0.000; db ans = Inf; 
    for(db i = 0; i < n; i++)
    {
        for(db j = 1; j <= l; j++)
        {
            for(db k = 0; k <= m; k++)
            {
                dp[i+1][j][k] = min(dp[i+1][j][k], dp[i][j][k]);  
                dp[i+1][j][k+1] = min(dp[i+1][j][k+1], dp[i][j][k] + v[i].sd / l); 
                if(v[i].fs != Inf)
                {
                    dp[i+1][j+1][k+1] = min(dp[i+1][j+1][k+1], dp[i][j][k] + v[i].fs / j); 
                } 
            }
        }
        ans = min(ans, dp[i+1][l][m]); 
    }
    return ans; 
}

double ternary_search(double l, double r)
{
    double eps = 1e-2, ans = Inf;              //set the error limit here
    while (r - l > eps) 
    {
        double m1 = l + (r - l) / 3;
        double m2 = r - (r - l) / 3;
        double f1 = f((long) m1);      //evaluates the function at m1
        double f2 = f((long) m2);      //evaluates the function at m2
        //cout << l << " " << r << " " << m1 << " " << (int) f1 << " " << m2 << " " << (int) f2 << endl; 
        ans = min(ans, min(f1, f2)); 
        if (f1 > f2)
            l = m1;
        else
            r = m2;
    }
   // printdb(ans, 6); 
    return ans;  //return the min of f(x) in [l, r]
}
 
void solve()
{
    cin >> n >> m; 
    v.assign(n, { 0, 0 }); 
    for(auto& u : v) 
    {
        cin >> u.sd >> u.fs;
        if(u.fs == -1) u.fs = Inf;  
    } 
    sort(all(v)); //printdb(f(2.0), 5);
    
    printdb(ternary_search(1, m), 5); 
}
 
int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
 
    int Q = 1; //cin >> Q;
 
    while (Q--)
    {
        solve();
    }
 
    return 0;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 5
• Subtask 3: 0 / 11
• Subtask 4: 0 / 12
• Subtask 5: 0 / 33
• Subtask 6: 0 / 11
• Subtask 7: 0 / 23