Submission #2368765

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Source Code Expand

#include "bits/stdc++.h"
#define in std::cin
#define out std::cout
#define rep(i,N) for(int i=0;i<N;++i)
typedef long long int LL;

const long double eps = 0.0000000001;
std::vector<long double>x(3), y(3), edge(3);
long double r1, r2;

long double triangleS(long double px1, long double py1, long double px2, long double py2, long double px3, long double py3)
{
	return abs((px1 - px3)*(py2 - py3) - (px2 - px3)*(py1 - py3)) / 2.;
}

bool check(long double x)
{
	r2 = r1 - x;
	auto ll = edge[2] * r2 / r1;
	return ll >= x * 2;
}

int main()
{
	rep(i, 3) in >> x[i] >> y[i];
	rep(i, 3) edge[i] = sqrt((x[i] - x[(i + 1) % 3])*(x[i] - x[(i + 1) % 3]) + (y[i] - y[(i + 1) % 3])*(y[i] - y[(i + 1) % 3]));
	std::sort(edge.begin(), edge.end());
	r1 = 2. * triangleS(x[0], y[0], x[1], y[1], x[2], y[2]) / (edge[0] + edge[1] + edge[2]);
	long double l = 0., r = 114514.;
	while (r - l > eps)
	{
		auto m = (r + l) / 2;
		if (check(m)) l = m;
		else r = m;
	}
	out << std::fixed << std::setprecision(12);
	out << l << std::endl;
	return 0;
}

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Judge Result