Time Limit: 1000MS | Memory Limit: 65536K | |
Total Submissions: 8176 | Accepted: 2862 |
Description
In a certain course, you take n tests. If you get ai out of bi questions correct on test i, your cumulative average is defined to be
.
Given your test scores and a positive integer k, determine how high you can make your cumulative average if you are allowed to drop any k of your test scores.
Suppose you take 3 tests with scores of 5/5, 0/1, and 2/6. Without dropping any tests, your cumulative average is . However, if you drop the third test, your cumulative average becomes .
Input
The input test file will contain multiple test cases, each containing exactly three lines. The first line contains two integers, 1 ≤ n ≤ 1000 and 0 ≤ k < n. The second line contains n integers indicating ai for all i. The third line contains n positive integers indicating bi for all i. It is guaranteed that 0 ≤ ai ≤ bi ≤ 1, 000, 000, 000. The end-of-file is marked by a test case with n = k = 0 and should not be processed.
Output
For each test case, write a single line with the highest cumulative average possible after dropping k of the given test scores. The average should be rounded to the nearest integer.
Sample Input
3 1
5 0 2
5 1 6
4 2
1 2 7 9
5 6 7 9
0 0
Sample Output
83
100
题解:给你n个数,让求删除k个数后
的最大值;01分数规划;
代码:
#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cmath>
using namespace std;
const int MAXN=;
struct Node{
int a,b;
};
Node dt[MAXN];
double d[MAXN];
int n,k;
bool fsgh(double R){
double sum=;
for(int i=;i<n;i++)d[i]=dt[i].a-R*dt[i].b;
sort(d,d+n);
for(int i=n-;i>=n-k;i--)sum+=d[i];
return sum>?true:false;
}
double erfen(double l,double r){
double mid;
while(r-l>1e-){
mid=(l+r)/;
if(fsgh(mid))l=mid;
else r=mid;
}
return mid;
}
int main(){
while(scanf("%d%d",&n,&k),n|k){
double mx=;
k=n-k;
for(int i=;i<n;i++)scanf("%d",&dt[i].a);
for(int i=;i<n;i++)scanf("%d",&dt[i].b),mx=max(1.0*dt[i].a/dt[i].b,mx);
printf("%.0f\n",erfen(,mx)*);
}
return ;
}