47 lines
1.1 KiB
C++
47 lines
1.1 KiB
C++
#include<stdio.h>
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#include<iostream>
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#include<string.h>
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#include<queue>
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using namespace std;
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const int MAXN=500010;
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int dp[MAXN];
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int q[MAXN];
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int sum[MAXN];
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int head,tail,n,m;
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int getDP(int i,int j)
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{
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return dp[j]+m+(sum[i]-sum[j])*(sum[i]-sum[j]);
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}
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int getUP(int j,int k)
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{
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return dp[j]+sum[j]*sum[j]-(dp[k]+sum[k]*sum[k]);
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}
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int getDOWN(int j,int k)
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{
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return 2*(sum[j]-sum[k]);
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}
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int main()
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{
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while(scanf("%d%d",&n,&m)==2)
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{
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for(int i=1;i<=n;i++)
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scanf("%d",&sum[i]);
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sum[0]=dp[0]=0;
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for(int i=1;i<=n;i++)
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sum[i]+=sum[i-1];
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head=tail=0;
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q[tail++]=0;
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for(int i=1;i<=n;i++)
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{
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while(head+1<tail && getUP(q[head+1],q[head])<=sum[i]*getDOWN(q[head+1],q[head]))
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head++;
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dp[i]=getDP(i,q[head]);
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while(head+1<tail && getUP(i,q[tail-1])*getDOWN(q[tail-1],q[tail-2])<=getUP(q[tail-1],q[tail-2])*getDOWN(i,q[tail-1]))
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tail--;
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q[tail++]=i;
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}
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printf("%d\n",dp[n]);
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}
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return 0;
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}
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