Submission #1319444

#	Time	Username	Problem	Language	Result	Execution time	Memory
1319444		simona1230	Feast (NOI19_feast)	C++20	0 / 100	81 ms	12036 KiB

feast

#include <bits/stdc++.h>

using namespace std;
long long n,k,a[300001];
void read()
{
    cin>>n>>k;
    for(long long i=1;i<=n;i++)
        cin>>a[i];
}

long long dp[300001][2];
long long cnt[300001][2];

pair<long long,long long> group(long long x)
{
    //cout<<"! "<<x<<endl;
    dp[0][1]=-1e18;

    for(long long i=1;i<=n;i++)
    {
        dp[i][0]=dp[i-1][0];
        cnt[i][0]=cnt[i-1][0];

        if(dp[i][0]<dp[i-1][1])
        {
            dp[i][0]=dp[i-1][1];
            cnt[i][0]=cnt[i-1][1];
        }

        if(dp[i-1][0]==dp[i-1][1])
            cnt[i][0]=max(cnt[i-1][0],cnt[i-1][1]);

        dp[i][1]=dp[i-1][1]+a[i];
        cnt[i][1]=cnt[i-1][1];

        if(dp[i][1]<max(dp[i-1][1],dp[i-1][0])+a[i]-x)
        {
            dp[i][1]=max(dp[i-1][1],dp[i-1][0])+a[i]-x;
            cnt[i][1]=cnt[i-1][0]+1;
        }

        if(dp[i-1][1]==max(dp[i-1][1],dp[i-1][0])-x)
            cnt[i][1]=max(cnt[i-1][1],cnt[i-1][0]+1);

        //cout<<i<<" "<<dp[i][0]<<" "<<dp[i][1]<<" "<<cnt[i][0]<<" "<<cnt[i][1]<<endl;
    }

    if(dp[n][0]>dp[n][1])return {dp[n][0],cnt[n][0]};
    if(dp[n][0]<dp[n][1])return {dp[n][1],cnt[n][1]};

    return {dp[n][0],max(cnt[n][0],cnt[n][1])};
}

void solve()
{
    long long ans=0;
    long long l=0,r=1e18;
    while(l<=r)
    {
        long long m=(l+r)/2;
        pair<long long,long long> g=group(m);

        if(g.second>=k)
        {
            //cout<<"in "<<g.first<<" "<<g.second<<endl;
            ans=max(ans,g.first+m*k);
            l=m+1;
        }
        else r=m-1;
    }

    cout<<ans<<endl;
}

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	read();
	solve();
	return 0;
}
/*
10 4
2 0 1 1 0 1 1 1 1 1
*/

• Subtask 1: 0 / 4
• Subtask 2: 0 / 8
• Subtask 3: 0 / 18
• Subtask 4: 0 / 10
• Subtask 5: 0 / 11
• Subtask 6: 0 / 20
• Subtask 7: 0 / 29