Submission #80448

#	Time	Username	Problem	Language	Result	Execution time	Memory
80448		igzi	Homecoming (BOI18_homecoming)	C++17	62 / 100	1064 ms	141864 KiB

homecoming

#include <bits/stdc++.h>
#include "homecoming.h"
#define maxN 2000005

using namespace std;

int n,k,i,a[maxN],b[maxN];
long long dp[maxN],sb[maxN],tmp[maxN],p[maxN],q[maxN];

long long dp0(int n,int k,long long a[],long long b[]){
long long i,ans=0;
deque <long long> dq;
sb[n-1]=b[n-1];
for(i=n-2;i>=0;i--) sb[i]=sb[i+1]+b[i];
dp[n-1]=a[n-1]-b[n-1];
tmp[n-1]=max((long long) 0,dp[n-1]);
ans=tmp[n-1];
dq.push_back(n-1);
for(i=n-2;i>=0;i--){
    long long x=dq.front();
    dp[i]=a[i]+dp[x]-sb[i]+sb[x];
    if(i+k<n) dp[i]=max(dp[i],tmp[i+k]+a[i]-sb[i]+sb[i+k]);
    ans=max(ans,dp[i]);
    tmp[i]=ans;
    if(dq.front()==i+k) dq.pop_front();
    while(dq.size() && dp[dq.back()]+sb[dq.back()]<=dp[i]+sb[i]){
        dq.pop_back();
    }
    dq.push_back(i);
}
return ans;
}

long long solve(int n,int k,int a[],int c[]){
long long ans=0,s;
int i,j;
for(i=0;i<n;i++) b[i]=c[i];
for(j=0;j<k;j++){
s=0;
for(i=0;i<n;i++){
    p[i]=a[(i+j)%n];
    if(i>=k) q[i]=b[(i+j)%n];
    else q[i]=0;
    if(i<k) s+=b[(i+j)%n];
    }
    ans=max(ans,dp0(n,k,p,q)-s);
}
for(i=k;i<n;i++){
    p[i-k]=a[i];
    q[i-k]=b[i];
}
for(i=n-k;i<n;i++){
    p[i]=0;
    q[i]=b[(i+k)%n];
}
ans=max(ans,dp0(n,k,p,q));
return ans;
}

• Subtask 1: 13 / 13
• Subtask 2: 18 / 18
• Subtask 3: 31 / 31
• Subtask 4: 0 / 38