I Think I Need a Houseboat


Time Limit: 1000MS

 

Memory Limit: 10000K

Total Submissions: 96615

 

Accepted: 42018


Description


Fred Mapper is considering purchasing some land in Louisiana to build his house on. In the process of investigating the land, he learned that the state of Louisiana is actually shrinking by 50 square miles each year, due to erosion caused by the Mississippi River. Since Fred is hoping to live in this house the rest of his life, he needs to know if his land is going to be lost to erosion. 

After doing more research, Fred has learned that the land that is being lost forms a semicircle. This semicircle is part of a circle centered at (0,0), with the line that bisects the circle being the X axis. Locations below the X axis are in the water. The semicircle has an area of 0 at the beginning of year 1. (Semicircle illustrated in the Figure.) 

1005 I Think I Need a Houseboat（数学题）_poj


Input


The first line of input will be a positive integer indicating how many data sets will be included (N). Each of the next N lines will contain the X and Y Cartesian coordinates of the land Fred is considering. These will be floating point numbers measured in miles. The Y coordinate will be non-negative. (0,0) will not be given.


Output


For each data set, a single line of output should appear. This line should take the form of: “Property N: This property will begin eroding in year Z.” Where N is the data set (counting from 1), and Z is the first year (start from 1) this property will be within the semicircle AT THE END OF YEAR Z. Z must be an integer. After the last data set, this should print out “END OF OUTPUT.”


Sample Input


2 1.0 1.0 25.0 0.0


Sample Output


Property 1: This property will begin eroding in year 1. Property 2: This property will begin eroding in year 20. END OF OUTPUT.


Hint


1.No property will appear exactly on the semicircle boundary: it will either be inside or outside. 
2.This problem will be judged automatically. Your answer must match exactly, including the capitalization, punctuation, and white-space. This includes the periods at the ends of the lines. 
3.All locations are given in miles.


Source


​​Mid-Atlantic 2001​​



题意：


半圆表示一块面积可扩展的区域，开始时，面积是0，在（0,0）处开始以每年50平方米的速度同样呈半圆扩展，输入一个正整数N，然后输入N对坐标，对于每一对坐标值：求出面积扩展到该点的年数，坐标值单位为米。




AC代码： 


#include <iostream>
#include <cmath>
using namespace std;
double pi=3.1415926;
int main()
{
    int k,count=1;
    double s,x,y;
    cin>>k;
    while(k--)
    {
        cin>>x>>y;
        s=(pi/2)*(x*x+y*y); //过点(x,y)的半圆的面积 
        cout<<"Property "<<count++<<": This property will begin eroding in year "<<(int)(s/(double)50+1)<<"."<<endl;
    }
    cout<<"END OF OUTPUT."<<endl;
    return 0;
}