Submission #973641

#	Time	Username	Problem	Language	Result	Execution time	Memory
973641		berr	Let's Win the Election (JOI22_ho_t3)	C++17	0 / 100	2554 ms	2644 KiB

Main

#include <bits/stdc++.h>
using namespace std;
const int N = 505;
 
double dp[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]; 
    });
    if(n!=k){

        auto calc=[&](int e){
           
            for(int i=0; i<=n+1; i++){
                for(int l=0; l<=n+1; l++){
                    dp[i][l]=1e9;
                }
            }
         
            dp[0][0]=0;
            for(int i=0; i<n; i++){
                for(int l=e; l>=0; l--){
                    for(int x=n; x>=0; x--){
                      //  cout<<(double)a[i][1]/(double)(l+1)<<"\n";
                        if(a[i][1]!=-1)
                            dp[l+1][x] =min<double>(dp[l+1][x], dp[l][x]+(double)a[i][1]/(double)(l+1));
                        dp[l][x+1]=min<double>(dp[l][x+1], dp[l][x]+((double)a[i][0]/(double)(e+1)));
                    }
                }
            }

            return dp[e][k-e];

        };
        double ans=1e9;
        for(int i=0; i<=k; i++){
            ans=min(ans, calc(i));
        }
        
        cout<<setprecision(9)<<ans<<"\n";
    }
    else{
        vector<double> pref(n), suf(n+1);

        for(int i=0; i<n; i++){
            if(a[i][1]==-1) break;

            pref[i]+=(double)(a[i][1])/(double)(i+1);

            if(i>0) pref[i]+=pref[i-1];
        }

        for(int i=n-1; i>=0; i--){
            suf[i]=a[i][0];
             suf[i]+=suf[i+1];
        }

        double ans=suf[0];

        for(int i=0; i<n; i++){
            if(a[i][1]==-1) break;
            else{
                ans=min<double>(ans, pref[i]+suf[i+1]/(i+2));
            }
        }

        cout<<ans;
    }
}

• 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