Submission #978901

#	Time	Username	Problem	Language	Result	Execution time	Memory
978901		Kiet07	Feast (NOI19_feast)	C++14	100 / 100	159 ms	15196 KiB

feast

#include<bits/stdc++.h>
using namespace std;
#define int long long
int n,k,a[300005];
pair<int,int>find(int x){
	pair<int,int> dp[n][2];
	dp[0][0]={0,0};
	dp[0][1]={a[0]-x,1};
	for(int i=1;i<n;i++){
		dp[i][0]=max(dp[i-1][0],dp[i-1][1]);
		dp[i][1]=max(make_pair(dp[i-1][1].first+a[i],dp[i-1][1].second),make_pair(dp[i-1][0].first+a[i]-x,dp[i-1][0].second+1));
	}
	return max(dp[n-1][0],dp[n-1][1]);
}
signed main()
{
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	cin>>n>>k;
	for(int i=0;i<n;i++){
		cin>>a[i];
	}
	int l=0,r=1e18,ans=0,res=0;
	while(l<=r){
		int m=(l+r)/2;
		auto it=find(m);
		if(it.second>=k){
			ans=m;
			l=m+1;
		}
		else{
			r=m-1;
		}
	}
	cout<<find(ans).first+ans*k;
	return 0;
}

Compilation message (stderr)

feast.cpp: In function 'int main()':
feast.cpp:22:23: warning: unused variable 'res' [-Wunused-variable]
   22 |  int l=0,r=1e18,ans=0,res=0;
      |                       ^~~

• Subtask 1: 4 / 4
• Subtask 2: 8 / 8
• Subtask 3: 18 / 18
• Subtask 4: 10 / 10
• Subtask 5: 11 / 11
• Subtask 6: 20 / 20
• Subtask 7: 29 / 29