Submission #1313035

#TimeUsernameProblemLanguageResultExecution timeMemory
1313035boclobanchatK blocks (IZhO14_blocks)C++20
100 / 100
269 ms2960 KiB
#include<bits/stdc++.h>
using namespace std;
const int MAXN=1e5+5;
const int INF=1e9;
int fen[MAXN],A[MAXN],dp[MAXN],L[MAXN],R[MAXN],pre[MAXN];
stack<int> st;
void update(int i,int n,int val) { for(;i<=n;i+=i&-i) fen[i]=min(fen[i],val); }
int get(int i) { int ans=INF;for(;i;i-=i&-i) ans=min(ans,fen[i]);return ans; }
int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n,k;
	cin>>n>>k;
	for(int i=1;i<=n;i++) cin>>A[i];
	for(int i=1;i<=n;i++)
	{
		while(!st.empty()&&A[i]>A[st.top()]) st.pop();
		if(st.empty()) L[i]=1;
		else L[i]=st.top()+1;
		st.push(i);
	}
	while(!st.empty()) st.pop();
	for(int i=n;i;i--)
	{
		while(!st.empty()&&A[i]>=A[st.top()]) st.pop();
		if(st.empty()) R[i]=n;
		else R[i]=st.top()-1;
		st.push(i);
	}
	for(int i=1;i<=n;i++) pre[i]=INF;
	for(int i=1;i<=k;i++)
	{
		for(int j=1;j<=n+1;j++) fen[j]=INF;
		dp[0]=INF;
		for(int j=1;j<=n;j++)
		{
			update(n+1-R[j-1],n+1,pre[j-1]);
			dp[j]=get(n+2-L[j])+A[j];
		}
		for(int j=0;j<=n;j++) pre[j]=dp[j];
	}
	int ans=INF;
	for(int i=1;i<=n;i++) if(R[i]==n) ans=min(ans,dp[i]);
	cout<<ans;
}
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