Submission #1570853

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
#define int long long

typedef long long ll;
typedef unsigned long long ull;
typedef unsigned __int128 HASH;
typedef pair<int,int> pii;
typedef pair<ll, ll> pll;
typedef pair<ull, ull> pullull;
typedef pair<ll,int> plli;
typedef pair<double, int> pdbi;
typedef pair<int,pii> pipii;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<pii> vpii;
typedef vector<vector<int>> mat;

#define rep(i,n) for (int i=0;i<(n);i++)
#define rep2(i,a,b) for (int i=(a);i<(b);i++)
#define rrep(i,n) for (int i=(n);i>0;i--)
#define rrep2(i,a,b) for (int i=(a);i>b;i--)
#define pb push_back
#define fi first
#define se second
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()

const ll hmod1 = 999999937;
const ll hmod2 = 1000000000 + 9;
const ll INF = 1<<30;
const ll mod = 1000000000 + 7;
const int dx4[4] = {1, 0, -1, 0};
const int dy4[4] = {0, 1, 0, -1};
const int dx8[8] = {1, 1, 1, 0, 0, -1, -1, -1};
const int dy8[8] = {0, 1, -1, 1, -1, 0, 1, -1};
const double pi = 3.141592653589793;

#define addm(X, Y) ((X) = ((X) + (Y) % mod) % mod)

double x[3], y[3];
double e[3];
double cs[3];
double ang[3];

bool inside(double r) {
    rep(i, 3) {
        double xx1,xx2;
        xx1 = r / tan(ang[i]); xx2 = r / tan(ang[(i + 1) % 3]);
        if (xx1 + xx2 + 2 * r + 1e-14 <= e[(i + 2) % 3]) {
            return true;
        }
    }
    return false;
}

signed main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    rep(i, 3) cin >> x[i] >> y[i];
    rep(i, 3) e[i] = sqrt(pow(abs(x[(i + 1) % 3] - x[i]), 2) + pow(abs(y[(i + 1) % 3] - y[i]), 2));
    rep(i, 3) {
        cs[i] = (pow(e[(i + 2) % 3], 2) + pow(e[(i + 1) % 3], 2) - pow(e[i], 2)) / (2 * e[(i + 1) % 3] * e[(i + 2) % 3]);
        ang[i] = acos(cs[i]) / 2;
    }
    double l = 0;
    double r = 100000;
    rep(i, 100) {
        double m = (r + l) / 2;
        if (inside(m)) l = m;
        else r = m;
    }
    cout << fixed << setprecision(12) << l << endl;
}

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