这是100分程序 f[i]=f[j]+ A*(sx[i]-sx[j])(sx[i]-sx[j])+B(sx[i]-sx[j])+C f[i]= f[j] + Asx[i]^2 + Asx[j]^2 - 2Asx[i]sx[j] + Bsx[i] - Bsx[j] + C 2Asx[i]sx[j] + f[i] - Asx[i]^2 - Bsx[i]- C = f[j] + Asx[j]^2 - Bsx[j] yj=f[j] + Asx[j]^2 - Bsx[j] xj=2.0Asx[j] k=sx[i] b= f[i] - Asx[i]^2 - Bsx[i] -C

#include <bits/stdc++.h>
using namespace std;
const int N=1110000;
typedef long long LL;
LL  x[N],sx[N],f[N],A,B,C;
int q[N];
inline double X(int j){return 2.0*A*sx[j];}
inline double Y(int j){return 1.0*(f[j]+A*sx[j]*sx[j]-B*sx[j]);}
inline double slop(int j1,int j2){return (X(j2)==X(j1))?1e18*( Y(j2)-Y(j1) ):( Y(j2)-Y(j1) )/( X(j2)-X(j1) );}
int main()
{
    int n;scanf("%d",&n);scanf("%lld%lld%lld",&A,&B,&C);
    sx[0]=0;f[0]=0;
    for(int i=1;i<=n;i++)scanf("%lld",&x[i]),sx[i]=sx[i-1]+x[i]; 

    int l=1,r=1;q[1]=0;
    for(int i=1;i<=n;i++)
    {
        while(l<r && slop(q[l],q[l+1])<=1.0*sx[i] )l++;
        
        LL t=sx[i]-sx[q[l]];
        f[i]=f[q[l]]+ A*t*t + B*t + C ;
         
        while(l<r && slop(q[r-1],q[r])>=slop(q[r],i) )r--;
         
        q[++r]=i;
    }
    printf("%lld\n",f[n]);
    return 0;
}

/*
这是100分程序
f[i]=f[j]+ A*(sx[i]-sx[j])*(sx[i]-sx[j])+B*(sx[i]-sx[j])+C 
f[i]= f[j] + A*sx[i]^2 + A*sx[j]^2 - 2A*sx[i]*sx[j] + B*sx[i] - B*sx[j] + C
2A*sx[i]*sx[j]  +  f[i] - A*sx[i]^2 -  B*sx[i]- C    =    f[j] + A*sx[j]^2  - B*sx[j] 
yj=f[j] + A*sx[j]^2 - B*sx[j] 
xj=2.0*A*sx[j]
k=sx[i]
b= f[i] - A*sx[i]^2 -  B*sx[i] -C
*/ 
#include<bits/stdc++.h>
using namespace std;
const int N=1110000;
typedef long long LL;
LL  x[N],sx[N],f[N],A,B,C;
int q[N];
inline double X(int j){return 2.0*A*sx[j];}
inline double Y(int j){return 1.0*(f[j]+A*sx[j]*sx[j]-B*sx[j]);}
inline double slop(int j1,int j2){return (X(j2)==X(j1))?1e18*( Y(j2)-Y(j1) ):( Y(j2)-Y(j1) )/( X(j2)-X(j1) );}
int main()
{
    int n;scanf("%d",&n);scanf("%lld%lld%lld",&A,&B,&C);
    sx[0]=0;f[0]=0;
    for(int i=1;i<=n;i++)scanf("%lld",&x[i]),sx[i]=sx[i-1]+x[i]; 

    int l=1,r=1;q[1]=0;
    for(int i=1;i<=n;i++)
    {
        while(l<r && slop(q[l],q[l+1])<=1.0*sx[i] )l++;
        
        LL t=sx[i]-sx[q[l]];
        f[i]=f[q[l]]+ A*t*t + B*t + C ;
         
        while(l<r && slop(q[r-1],q[r])>=slop(q[r],i) )r--;
         
        q[++r]=i;
    }
    printf("%lld\n",f[n]);
    return 0;
}