hdu 4258斜率优化 状态转移要仔细考虑

#include<iostream>
#include<cstring>
#include<algorithm>
#include<cstdio>
#include<vector>
#include<sstream>
#include<string>
#include<climits>
#include<stack>
#include<set>
#include<bitset>
#include<cmath>
#include<deque>
#include<map>
#include<queue>
#define iinf 2000000000
#define linf 1000000000000000000LL
#define dinf 1e200
#define eps 1e-5
#define all(v) (v).begin(),(v).end()
#define sz(x)  x.size()
#define pb push_back
#define mp make_pair
#define lng long long
#define sqr(a) ((a)*(a))
#define pii pair<int,int>
#define pll pair<lng,lng>
#define pss pair<string,string>
#define pdd pair<double,double>
#define X first
#define Y second
#define pi 3.14159265359
#define ff(i,xi,n) for(int i=xi;i<=(int)(n);++i)
#define ffd(i,xi,n) for(int i=xi;i>=(int)(n);--i)
#define ffl(i,r) for(int i=head[r];i!=-1;i=edge[i].next)
#define cc(i,j) memset(i,j,sizeof(i))
#define two(x)			((lng)1<<(x))
#define N 1000002
#define M 1000000
#define lson l , mid , rt << 1
#define rson mid + 1 , r , rt << 1 | 1
#define Mod  n
#define Pmod(x) (x%Mod+Mod)%Mod
using namespace std;
typedef vector<int>  vi;
typedef vector<string>  vs;
typedef unsigned int uint;
typedef unsigned lng ulng;
template<class T> inline void checkmax(T &x,T y){if(x<y) x=y;}
template<class T> inline void checkmin(T &x,T y){if(x>y) x=y;}
template<class T> inline T Min(T x,T y){return (x>y?y:x);}
template<class T> inline T Max(T x,T y){return (x<y?y:x);}
template<class T> T gcd(T a,T  b){return (a%b)==0?b:gcd(b,a%b);}
template<class T> T lcm(T a,T b){return a*b/gcd(a,b);}
template<class T> T Abs(T a){return a>0?a:(-a);}
template<class T> inline T lowbit(T n){return (n^(n-1))&n;}
template<class T> inline int countbit(T n){return (n==0)?0:(1+countbit(n&(n-1)));}
template<class T> inline bool isPrimeNumber(T n)
{if(n<=1)return false;for (T i=2;i*i<=n;i++) if (n%i==0) return false;return true;}
lng n,dp[N],q[N],f,r,c,a[N];
int main()
{
    while(scanf("%I64d%I64d",&n,&c)==2)
    {
        if(n==0&&c==0) break;
        cc(dp,0);
        q[0]=0;
        f=0,r=0;
        a[0]=0;
        ff(i,1,n)
        {
            scanf("%I64d",a+i);
        }
        ff(i,1,n){
            while(r>f)
            {
                int k=q[f+1],j=q[f];
                if(dp[k]+sqr(a[k+1])-dp[j]-sqr(a[j+1])<=(a[k+1]-a[j+1])*a[i]*2)
                ++f;
                else
                break;
            }
            dp[i]=dp[q[f]]+c+sqr(a[i]-a[q[f]+1]);
               while(r>f)
            {
                int k=q[r],j=q[r-1];
                if((dp[i]-dp[k]+sqr(a[i+1])-sqr(a[k+1]))*(a[k+1]-a[j+1])<=(dp[k]+sqr(a[k+1])-dp[j]-sqr(a[j+1]))*(a[i+1]-a[k+1]))
                --r;
                else
                break;
            }
            q[++r]=i;
        }
        printf("%I64d\n",dp[n]);
    }
    return 0;
}