zoukankan      html  css  js  c++  java
  • Print Article

    Problem Description
    Zero has an old printer that doesn't work well sometimes. As it is antique, he still like to use it to print articles. But it is too old to work for a long time and it will certainly wear and tear, so Zero use a cost to evaluate this degree. One day Zero want to print an article which has N words, and each word i has a cost Ci to be printed. Also, Zero know that print k words in one line will cost
    M is a const number. Now Zero want to know the minimum cost in order to arrange the article perfectly.
     
    Input
    There are many test cases. For each test case, There are two numbers N and M in the first line (0 ≤ n ≤ 500000, 0 ≤ M ≤ 1000). Then, there are N numbers in the next 2 to N + 1 lines. Input are terminated by EOF.
     
    Output
    A single number, meaning the mininum cost to print the article.
     
    Sample Input
    5 5 5 9 5 7 5
     
    Sample Output
    230
     
    Author
    Xnozero
     
    Source
     
    Recommend
    zhengfeng
    ***************************************************************************************
    讲解的很清楚,有图又推导,不过看了很长时间才看懂,关键求斜率推导式
    ***************************************************************************************
     1 #include<iostream>
     2 #include<cstring>
     3 #include<string>
     4 #include<cstdio>
     5 #include<cmath>
     6 #define  L  long long
     7 using namespace std;
     8 L dp[500005];
     9 L sum[500005];
    10 int  q[500005];
    11 int n,m,i,j;
    12 void  init()
    13 {
    14     for(i=1;i<=n;i++)
    15      cin>>sum[i];
    16     for(i=2;i<=n;i++)
    17       sum[i]+=sum[i-1];
    18 
    19 }
    20 L getdp(int i,int j)//求dp
    21     {
    22         return dp[j]+m+(sum[i]-sum[j])*(sum[i]-sum[j]);
    23     }
    24 L  getup(int j,int k)//分子
    25  {
    26      return   (dp[j]+sum[j]*sum[j])-(dp[k]+sum[k]*sum[k]);
    27  }
    28 L getdown(int j,int k)//分母
    29   {
    30       return  2*(sum[j]-sum[k]);
    31   }
    32 int main()
    33 {
    34    while(scanf("%d %d",&n,&m)!=EOF)
    35     {
    36         memset(dp,0,sizeof(dp));
    37         memset(sum,0,sizeof(sum));
    38         memset(q,0,sizeof(q));
    39         init();
    40       int head=0;
    41     int tail=0;
    42      q[0]=dp[0]=0;
    43      tail++;
    44      for(i=1;i<=n;i++)
    45       {
    46           while(head+1<tail&&getup(q[head+1],q[head])<=sum[i]*getdown(q[head+1],q[head]))
    47             head++;
    48             dp[i]=getdp(i,q[head]);
    49           while(head+1<tail&&getup(i,q[tail-1])*getdown(q[tail-1],q[tail-2])<=getup(q[tail-1],q[tail-2])*getdown(i,q[tail-1]))//删去一定不满足条件的点
    50             tail--;
    51           q[tail++]=i;
    52       }
    53 
    54   cout<<dp[n]<<endl;
    55 }
    56   return 0;
    57 
    58 
    59 
    60 }
    View Code
  • 相关阅读:
    利用哈希map快速判断两个数组的交集
    TCP协议中的三次握手和四次挥手(图解)-转
    PC,移动端H5实现实现小球加入购物车效果
    HQL和SQL的区别
    Java泛型详解,通俗易懂只需5分钟
    经典的 Fork 炸弹解析
    Java并发之AQS详解
    Java不可重入锁和可重入锁的简单理解
    Codeforces 1215F. Radio Stations
    Codeforces 1215E. Marbles
  • 原文地址:https://www.cnblogs.com/sdau--codeants/p/3251238.html
Copyright © 2011-2022 走看看