Nyoj sprinkler (1) (simple greedy) and nyoj sprinkler greedy

Nyoj sprinkler (1) (simple greedy) and nyoj sprinkler greedy
Sprinkler (1) Time Limit: 3000 MS | memory limit: 65535 KB difficulty: 3

Description

There is a lawn with a length of 20 meters and a width of 2 meters. A sprinkler with a radius of Ri should be placed on the horizontal center, the effect of each sprinkler will make the circle with its center radius as the real number Ri (0 <Ri <15) moist, there are plenty of sprinkler I (1 <I <600), and you will surely be able to wet all the lawns. What you need to do is: select as few sprinkler as possible, wet all the lawns.

Input

The first line m indicates that there are m groups of test data
The first line of each set of test data has an integer n, n indicates a total of n sprinkler devices, and the subsequent line has n real number ri, ri indicates the radius of the circle covered by the sprinkler.

Output

Number of devices used for output

Sample Input

252 3.2 4 4.5 6 101 2 3 1 2 1.2 3 1.1 1 2

Sample output

25

Source

[Miao Dongdong] original

Uploaded

Miao Dongdong

The Code is as follows:

#include<stdio.h>#include<math.h> int main(){int t,n,i,j;double k,w,a[660];scanf("%d",&t);while(t--){scanf("%d",&n);for(i=0;i<n;i++)scanf("%lf",&a[i]);for(i=0;i<n;i++){for(j=i+1;j<n;j++){if(a[i]<a[j])k=a[i],a[i]=a[j],a[j]=k;}}w=20;int count=0;for(i=0;w>=0;i++){w-=2*sqrt(a[i]*a[i]-1);count++;}printf("%d\n",count);}return 0;}

An Automatic Sprinkler with a maximum distance of 20 meters. This sprinkler can spray flowers and plants in a variety of areas.

If there is no cover within 125 m², it's very easy. What is the circular area. 20 meters is the radius (r), S (area of the circle) = π r², π = 3.14
 
(One-dimensional equation) Water Sprinkler should be built in the center of a Circular Pool

Guarantee h =-(x-1) 2 + 2.25> 0

-0.5 <x <2.5

Based on the question 0 <= x <2.5,
So the pool radius must be at least MB before being sprayed out of the pool.