愿你有一天能和你重要的人重逢
这题就是这题稍稍变了一丁点(几乎没变)
解析可参考上一篇博客
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
#include<cmath>
#include<vector>
#include<set>
#include<queue>
#include<limits.h>
#include<string.h>
#include<map>
#include<list>
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long long LL;
typedef long double db;
#define inf int(0x3f3f3f3f)
#define mod int(1e9+7)
#define eps double(1e-6)
#define pi acos(-1.0)
#define lson root << 1
#define rson root << 1 | 1
#define pb push_back
ll dp[100005<<1];
ll sum[100005<<1];
ll q[100005<<1];
ll head,tail,n,m;
ll len;
ll getDP(int i,int j)
{
return dp[j]+(len+sum[i]-sum[j]-m)*(len+sum[i]-sum[j]-m);
}
ll getUP(int j,int k)
{
return (dp[j]+sum[j]*sum[j]+2ll*(m-len)*sum[j])-(dp[k]+sum[k]*sum[k]+2ll*(m-len)*sum[k]);
}
ll getDOWN(int j,int k)
{
return 2ll*(sum[j]-sum[k]);
}
ll a[100005<<1];
int main()
{
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin>>n>>len>>m;
for(int i=1; i<=n; i++)
cin>>a[i];
sum[0]=dp[0]=0;
for(int i=1; i<=n; i++)
sum[i]=sum[i-1]+a[i];
for(int i=1; i<=n; i++)
sum[i]+=i;
head=tail=0;
q[tail++]=0;
for(int i=1; i<=n; i++)
{
while(head+1<tail && getUP(q[head+1],q[head])<=(sum[i])*getDOWN(q[head+1],q[head]))
head++;
dp[i]=getDP(i,q[head]);
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]))
tail--;
q[tail++]=i;
}
cout<<dp[n]<<endl;
}