CatchingShadeinFlatland99.cpp

#include <iostream>
#include <iomanip>
#include <cmath>
#define PI 3.14159265
using namespace std;

int main() {
	int n;
	while (cin >> n) {
		if (n == 0)
			return 0;
		int *x = new int[n];
		int *y = new int[n];
		int *r = new int[n];
		for (int i = 0; i < n; i++) {
			cin >> x[i] >> y[i] >> r[i];
		}
		double max = 0.0;
		for (double i = 0.0; i <= 360.0; i += 0.25) {
			double a = 500 * cos(i*PI / 180);
			double b = 500 * sin(i*PI / 180);
			double c = 0;//y intercept is zero
			double sum = 0.0;
			for (int j = 0; j < n; j++) {
				double dist = (a*x[j] + b * y[j] ) / sqrt(pow(a, 2) + pow(b, 2));//perpendicular distance from the line to the center of the circle
				if (dist < 0)
					continue;
				dist = x[j] * x[j] + y[j] * y[j] - dist * dist;
				if (dist < r[j]*r[j]) {
					sum += 2 * sqrt(pow(r[j], 2) - dist);//pythagoras
				}
			}
			if (sum > max)
				max = sum;
		}
		cout << setprecision(3) << fixed << max << endl;
	}
	return 0;
}