POJ 1005 & ZOJ 1049 & UVA 2363

思路：求出在x,y點的面積，除以每年的腐蝕面積，向上取整，使用ceil（）函數

#include <iostream>
 
using namespace std;
#define PI 3.141592653
 
 
int main()
{
    int test_num;
    cin >> test_num;
    double x,y;
    double area;
    int year;
    for(int i = 1 ; i <= test_num; i++)
    {
        cin >> x;
        cin >> y;
        area = (x * x + y * y) * PI / 2;
        year = int(area/50)+1;
        cout << "Property " << i <<": This property will begin eroding in year " << year <<"." <<endl;
    }
 
    cout << "END OF OUTPUT" << endl;
}