Submission #64457

#	Time	Username	Problem	Language	Result	Execution time	Memory
64457		TadijaSebez	Homecoming (BOI18_homecoming)	C++11	100 / 100	312 ms	135064 KiB

homecoming

#include <stdio.h>
#define ll long long
const int N=2000050;
const int M=2*N;
const ll inf=9e18;
ll max(ll a, ll b){ return a>b?a:b;}
ll sum[M],a[N],dp[N][2],b[M];
ll Get(int l, int r){ return sum[r]-sum[l-1];}
ll solve(int n, int k, int *A, int *B)
{
	int i,j;
	ll sol=0;
	for(i=1;i<=n;i++) a[i]=A[i-1],b[i]=-B[i-1];
	for(i=n+1;i<=n*2;i++) b[i]=b[i-n];
	for(i=1;i<=2*n;i++) sum[i]=sum[i-1]+b[i];
	dp[1][0]=0;
	dp[1][1]=-inf;
	for(i=2;i<=n;i++)
	{
		dp[i][0]=max(dp[i-1][0],dp[i-1][1]);
		dp[i][1]=max(dp[i-1][0]+Get(i,i+k-1)+a[i],dp[i-1][1]+a[i]+b[i+k-1]);
	}
	sol=max(sol,max(dp[n][0],dp[n][1]));
	dp[1][0]=-inf;
	dp[1][1]=a[1]+Get(1,k);
	for(i=2;i<=n;i++)
	{
		dp[i][0]=max(dp[i-1][0],dp[i-1][1]);
		if(i+k-1<=n) dp[i][1]=max(dp[i-1][0]+Get(i,i+k-1)+a[i],dp[i-1][1]+a[i]+b[i+k-1]);
		else dp[i][1]=max(dp[i-1][0]+Get(i,n)+a[i],dp[i-1][1]+a[i]);
	}
	sol=max(sol,max(dp[n][0],dp[n][1]));
	return sol;
}

Compilation message (stderr)

homecoming.cpp: In function 'long long int solve(int, int, int*, int*)':
homecoming.cpp:11:8: warning: unused variable 'j' [-Wunused-variable]
  int i,j;
        ^

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