Pro.ID10097 TitleRadio Coverage Title链接http://10.20.2.8/oj/exercise/problem?problem_id=10097 AC1 Submit1 Ratio100.00% 时间&空间限制描述Radio station 'ACM Rock' is broadcasting over the circular area with center in point (x0, y0) and radius R. In order to increase the auditorium, it were suggested to build several relay stations. N locations were selected as candidate sites for relay stations. Relay station placed in i-th location will cover a circular area with center in point (xi, yi) and radius ri, where center lies inside the area covered by the base station, (x0 - xi)2 + (y0 - yi)2 ≤ R2. Your task is to select a subset of sites for relay stations so that:
输入Input contains integer number N followed by real numbers x0 y0 R, followed by N triples of real numbers xi yi ri. 1 ≤ N ≤ 10, 0 ≤ xi, yi, x0, y0 ≤ 1000, 1 ≤ ri ≤ R ≤ 1000. 输出Description Radio station 'ACM Rock' is broadcasting over the circular area with center in point (x0, y0) and radius R. In order to increase the auditorium, it were suggested to build several relay stations. N locations were selected as candidate sites for relay stations. Relay station placed in i-th location will cover a circular area with center in point (xi, yi) and radius ri, where center lies inside the area covered by the base station, (x0 - xi)2 + (y0 - yi)2 ≤ R2. Your task is to select a subset of sites for relay stations so that:
Input Input contains integer number N followed by real numbers x0 y0 R, followed by N triples of real numbers xi yi ri. 1 ≤ N ≤ 10, 0 ≤ xi, yi, x0, y0 ≤ 1000, 1 ≤ ri ≤ R ≤ 1000. Output Output should contain a single real number --- the maximal coverage area with the absolute error less than 10-2. Sample Input 1 0 0 10 Sample Output 505.4816 Source 样例输入1 0 0 10 样例输出505.4816 作者 |