Submission #973991

#	Time	Username	Problem	Language	Result	Execution time	Memory
973991		berr	Let's Win the Election (JOI22_ho_t3)	C++17	100 / 100	191 ms	4448 KiB

Main

#include <bits/stdc++.h>
using namespace std;
const int N = 505;
 
double dp[N][N], mi[N][N];
 
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    
    int n, k; cin >> n >> k;
 
    vector<array<int, 2>> a(n);
 
    for(auto &[i, l]: a) cin >> i >> l;
 
    sort(a.begin(), a.end(), [&](auto x, auto y){
        if(x[1]==y[1]) return x[0] < y[0];
        else if(y[1]==-1) return true;
        else if(x[1]==-1) return false;
         return x[1]<y[1]; 
    });
    

    double ans=1e9;

    for(int i=0; i<=n; i++){
        for(int l=0; l<=n; l++){
            mi[i][l]=1e9;
        }
    }
    mi[n][0]=0;

    for(int i=n-1; i>=0; i--){
        mi[i][0]=0;

        for(int l=n; l>0; l--){

            mi[i][l]=min(mi[i+1][l], mi[i+1][l-1]+a[i][0]);
        }
    }


    auto calc=[&](int e){
       
        for(int i=0; i<=n+1; i++){
            for(int l=0; l<=n+1; l++){
                dp[i][l]=1e9;
            }
        }
     
        for(int i=0; i<=k; i++){
            if(a[i][1]==-1) break;
                dp[i][0]=(i==0?0:dp[i-1][0])+(double)a[i][0]/(double)(e+1);
            if(i>0)
                for(int l=e; l>=1; l--)
                dp[i][l] =min<double>(dp[i-1][l-1]+(double)a[i][1]/(double)(l), dp[i-1][l]+((double)a[i][0])/(double)(e+1)); 
            
            else dp[i][1]=a[i][1];
            
        }   

        for(int i=0; i<k; i++){
            if(mi[i+1][k-i-1]!=1e9&&dp[i][e]!=(1e9))
            ans=min(ans, dp[i][e]+(double)mi[i+1][k-i-1]/(double)(e+1));
        }

    };


    for(int i=1; i<=k; i++){
        calc(i);
    }

    ans=min(ans, mi[0][k]);

    cout<<fixed<<" "<<setprecision(9)<<ans<<"\n";
    
}

• 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