50分

#include<bits/stdc++.h>

using namespace std;

typedef long long LL;

const int N = 100010;

int n;
LL m[N],s[N];
LL L,f[N];

LL get_y(int t)
{
    return f[t]+s[t]*s[t]+2*L*s[t];
}

void solve(int l,int r)
{
    if(l>=r) return;
    int mid = l+r>>1;
    solve(l,mid);

    vector<int> v1,v2;

    for(int i=1;i<=n;i++)
    {
        if(m[i]>=l && m[i]<=mid) v1.push_back(i);
        if(m[i]>mid && m[i]<=r) v2.push_back(i);
    }

    int hh=0,tt=0,q[N],k=0;
    q[0] = 0;

    for(int i=0;i<v2.size();i++)
    {
        int t = v2[i];
        while(k<v1.size() && v1[k] < t) 
        {
            while(hh<tt && (get_y(v1[k]) - get_y(q[tt])) * (s[q[tt]] - s[q[tt-1]]) 
                <= (get_y(q[tt]) - get_y(q[tt-1])) * (s[v1[k]] - s[q[tt]])) tt--;
            q[++tt] = v1[k++];
        }
        while(hh<tt && get_y(q[hh+1]) - get_y(q[hh]) <= 2 * s[t] * (s[q[hh+1]]-s[q[hh]])) hh++;
        int j = q[hh];
        f[t] = min(f[t],f[j]+(s[t]-s[j]-L) * (s[t]-s[j]-L));
    }
    solve(mid+1,r);
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0),cout.tie(0);
    LL maxm = 0;
    cin>>n>>L;
    for(int i=1;i<=n;i++) cin>>s[i],s[i]+=s[i-1];
    for(int i=1;i<=n;i++) cin>>m[i],maxm = max(maxm,m[i]);
    memset(f,0x3f,sizeof f);
    f[0] = 0;
    solve(0,maxm+1);
    cout<<f[n]<<endl;
    return 0;
}