Submission #861660

#	Time	Username	Problem	Language	Result	Execution time	Memory
861660		Aiperiii	Homecoming (BOI18_homecoming)	C++17	100 / 100	111 ms	102484 KiB

homecoming

#include "homecoming.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define all(x) x.begin(),x.end()
#define ff first
#define ss second
const int N=2e6+6;
ll dp[N][2];
ll solve(int n,int k,int a[],int b[]){
    vector <ll> pr;
    ll sum=0;
    for(int i=0;i<n;i++){
        sum+=b[i];
        pr.push_back(sum);
    }
    dp[0][0]=-1e18;
    dp[0][1]=a[0]-pr[k-1];
    for(int i=1;i<n;i++){
        dp[i][0]=max(dp[i-1][0],dp[i-1][1]);
        ll val1=dp[i-1][1]+a[i];
        if(i+k-1<n){
            val1-=b[i+k-1];
        }
        ll val2=dp[i-1][0]+a[i]-pr[min(i+k-1,n-1)]+pr[i-1];
        dp[i][1]=max(val1,val2);
    }
    ll res1=max(dp[n-1][0],dp[n-1][1]);
    dp[0][0]=0;
    dp[0][1]=-1e18;
    for(int i=1;i<n;i++){
        dp[i][0]=max(dp[i-1][0],dp[i-1][1]);
        ll val1=dp[i-1][1]+a[i]-b[(i+k-1)%n];
        ll val2=dp[i-1][0]+a[i]-pr[min(i+k-1,n-1)]+pr[i-1];
        if(i+k-1>n-1){
            val2-=pr[i+k-1-n];
        }
        dp[i][1]=max(val1,val2);
    }
    ll res2=max(dp[n-1][0],dp[n-1][1]);
    return max(res1,res2);
}

• Subtask 1: 13 / 13
• Subtask 2: 18 / 18
• Subtask 3: 31 / 31
• Subtask 4: 38 / 38