Submission #69729

#	Time	Username	Problem	Language	Result	Execution time	Memory
69729		khohko	Homecoming (BOI18_homecoming)	C++17	31 / 100	261 ms	141576 KiB

homecoming

#include<bits/stdc++.h>
#include "homecoming.h"
using namespace std;
#define ll long long
#define fr first
#define sc second
#define pb push_back
#define ARRS ((ll)(6e6+100))
#define MAX ((ll)(1e16+100))


ll a[ARRS];
ll b[ARRS];
ll s[ARRS];
ll dp[ARRS][2];

ll sum(ll l,ll r){
	return s[r]-s[l-1];
}

long long solve(int n, int K, int *B, int *A){
	ll pas=0,p=0;
	for(int i=1; i<=n; i++){
		a[i]=A[i-1];
		a[i+n]=A[i-1];

		b[i]=B[i-1];
		b[i+n]=B[i-1];

		p-=a[i];
		p+=b[i];
	}
	for(int i=1; i<=2*n; i++)s[i]=s[i-1]+a[i];
	pas=max(pas,p);

	pair<ll,ll> mn={MAX,MAX};
	ll es=0,l=1;
	for(int i=1; i<=2*n; i++){
		//ll sm=0;
		//for(int j=i; j<=2*n; j++){
		//	sm-=a[j]-b[j];
		if(i-l>=K)es+=a[l]-b[l++];
		if(es>=0)es=0,l=i;
		es-=a[i]-b[i];
		mn=min(mn,{es,i-1});
	//	}
	}



	ll s=mn.sc;
	s++;
	s%=n;
	dp[0][0]=0;
	dp[0][1]=-MAX;
	for(int i=1; i<=n; i++){
		dp[i][0]=dp[i-1][0];
		dp[i][1]=-MAX;
		if(i>=K){
			dp[i][1]=max(dp[i][1],dp[i-K][0]+b[i-K+1+s]-sum(i-K+1+s,i+s));
			dp[i][1]=max(dp[i][1],dp[i-1][1]+b[i-K+1+s]-a[i+s]);
		}
		dp[i][0]=max(dp[i][0],dp[i][1]);
		//cout<<dp[i][0]<<" "<<dp[i][1]<<endl;
	}
	pas=max(pas,dp[n][0]);
	//cout<<endl;

	return pas;
}

Compilation message (stderr)

homecoming.cpp: In function 'long long int solve(int, int, int*, int*)':
homecoming.cpp:42:25: warning: operation on 'l' may be undefined [-Wsequence-point]
   if(i-l>=K)es+=a[l]-b[l++];
                        ~^~

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