1 #include<cstdio>
 2 #include<cstdlib>
 3 #include<iostream>
 4 #include<algorithm>
 5 using namespace std;
 6 const int N = 500100;
 7 #define For(i,n) for(int i=1;i<=n;i++)
 8 #define Rep(i,l,r) for(int i=l;i<=r;i++)
 9 
10 int n,M,sum[N],dp[N],q[N];
11 //  dp[i] = max{dp[j] + (sj-si)^2 + M}
12 //-> dp[k] - dp[j] + sk^2 - sj^2 
13 //    --------------------------   > 2si 时 j比k优 
14 //              sk - sj
15 
16 int Up(int i,int j){
17     return dp[i]+sum[i]*sum[i]-(dp[j]+sum[j]*sum[j]);
18 }
19 
20 int Down(int i,int j){
21     return sum[i]-sum[j]; 
22 }
23 
24 void DP(){
25     int l=0,r=1;
26     For(i,n){
27         while(l+1<r && Up(q[l],q[l+1])>=2*sum[i]*Down(q[l],q[l+1])) l++;
28         dp[i]=dp[q[l]] + (sum[i]-sum[q[l]])*(sum[i]-sum[q[l]]) + M;
29         while(l+1<r && Up(q[r-2],q[r-1])*Down(q[r-1],i)>=Up(q[r-1],i)*Down(q[r-2],q[r-1])) --r;
30         q[r++]=i;
31     } 
32     printf("%d\n",dp[n]);
33 }
34 
35 int main(){
36     while(scanf("%d%d",&n,&M)!=EOF){
37         q[0]=dp[0]=0;
38         For(i,n){
39             scanf("%d",&sum[i]);
40             sum[i]+=sum[i-1];
41         }
42         DP();
43     }
44     return 0;
45 }