呃呃呃，和平方的有什么区别吗。。
1 #include <bits/stdc++.h> 2 #define LL long long 3 #define lowbit(x) x&(-x) 4 #define inf 0x3f3f3f3f 5 #define eps 1e-5 6 #define N 1000005 7 using namespace std; 8 inline int ra() 9 { 10 int x=0,f=1; char ch=getchar(); 11 while (ch<'0' || ch>'9') {if (ch=='-') f=-1; ch=getchar();} 12 while (ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();} 13 return x*f; 14 } 15 LL sum[N],f[N]; 16 int A,B,C,n,q[N]; 17 double slope(int j, int k) 18 { 19 return (double)((f[j]+A*sum[j]*sum[j]-B*sum[j])-(f[k]+A*sum[k]*sum[k]-B*sum[k]))/(double)(2*A*(sum[j]-sum[k])); 20 } 21 int main(int argc, char const *argv[]) 22 { 23 n=ra(); A=ra(); B=ra(); C=ra(); 24 for (int i=1; i<=n; i++) sum[i]=sum[i-1]+ra(); 25 int l=0,r=0; 26 for (int i=1; i<=n; i++) 27 { 28 while (l<r && slope(q[l+1],q[l])<=(double)sum[i]) l++; 29 int t=q[l]; 30 f[i]=f[t]+A*(sum[i]-sum[t])*(sum[i]-sum[t])+B*(sum[i]-sum[t])+C; 31 while (l<r && slope(q[r],q[r-1])>=slope(i,q[r])) r--; 32 q[++r]=i; 33 } 34 cout<<f[n]; 35 return 0; 36 }