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ZOJ 3607 Lazier Salesgirl (贪心)
Lazier Salesgirl
Kochiya Sanae is a lazy girl who makes and sells bread. She is an expert at bread making and selling. She can sell the i-th customer a piece of bread for price pi. But she is so lazy that she will fall asleep if no customer comes to buy bread for more than w minutes. When she is sleeping, the customer coming to buy bread will leave immediately. It‘s known that she starts to sell bread now and the i-th customer come after ti minutes. What is the minimum possible value of w that maximizes the average value of the bread sold?
Input
There are multiple test cases. The first line of input is an integer T ≈ 200 indicating the number of test cases.
The first line of each test case contains an integer 1 ≤ n ≤ 1000 indicating the number of customers. The second line contains n integers 1 ≤ pi ≤ 10000. The third line contains nintegers 1 ≤ ti ≤ 100000. The customers are given in the non-decreasing order of ti.
Output
For each test cases, output w and the corresponding average value of sold bread, with six decimal digits.
Sample Input
241 2 3 41 3 6 1044 3 2 11 3 6 10
Sample Output
4.000000 2.5000001.000000 4.000000
Author: WU, Zejun
Contest: The 9th Zhejiang Provincial Collegiate Programming Contest
题意:
T个情况,每个情况有n个客人,第i个客人可赚p[i]元钱,第i个客人t[i]时间来,卖东西的女孩很懒,如果w时间内没人来就睡觉,后面来的客人就会刚来就走,求赚钱的平均值最大同时输出最小w.
这题采用贪心,如果t[i+1]-t[i]<maxtime时,那么后面一个客人能买到面包,如果t[i+1]-t[i]>maxtime那么就先把当前的情况记录下来,再往后去找
1 #include<cstdio> 2 #include<cstring> 3 #include<stdlib.h> 4 #include<algorithm> 5 using namespace std; 6 const int MAXN=1000+10; 7 int p[MAXN],t[MAXN]; 8 int main() 9 {10 //freopen("in.txt","r",stdin);11 int kase;12 scanf("%d",&kase);13 while(kase--)14 {15 int n;16 scanf("%d",&n);17 memset(p,0,sizeof(p));18 memset(t,0,sizeof(t));19 for(int i=1;i<=n;i++)20 scanf("%d",&p[i]);21 for(int i=1;i<=n;i++)22 scanf("%d",&t[i]);23 24 double maxtime=-1,time=0;25 double sum=0,av=0;26 for(int i=1;i<=n;i++)27 {28 sum+=p[i];29 if(maxtime<t[i]-t[i-1])30 maxtime=t[i]-t[i-1];31 32 if(maxtime<t[i+1]-t[i]&&sum>av*i)33 {34 av=sum/i;35 time=maxtime;36 }37 38 if(i==n)39 {40 if(av*i<sum)41 {42 av=sum/i;43 time=maxtime;44 }45 }46 }47 printf("%.6lf %.6lf\n",time,av);48 }49 return 0;50 }