我这是视频题解，你看不看

已在b站发布视频：BV1an6MBGE42

还有不会的可以私聊up哦

ac代码：

#include <bits/stdc++.h>
using namespace std;
#define sc second
#define fr first
#define int long long
#define itn long long
#define vi vector<int>
#define vvi vector<vector<int>>
#define pii pair<int, int>
#define endl '\n'
#define enld '\n'
#define all(a) a.begin(), a.end()
#define ui unordered_map<int, int>
#define double long double
const int N = 5e5 + 5;
// const int mod = 998244353;
// const int mod = 1e9 + 7;
double n, m, k, x, y, num, op, sum = 0, cnt = 0;
string s;
void _()
{
    double r, s, x0, y0, jiao;
    double s_mx;
    cin >> r >> x >> y >> s >> x0 >> y0;
    double h = sqrt((x - x0) * (x - x0) + (y - y0) * (y - y0));
    if (h >= r / 2)
    {
        s_mx = 3 * sqrt(3) / 4 * r * r;
    }
    else
    {
        s_mx = (r + h) * sqrt(r * r - h * h);
    }
    if (s_mx < s)
    {
        cout << -1;
        return;
    }
    if (y != y0 || x != x0)
        jiao = abs(atan(abs(y - y0) / abs(x - x0)));
    else
    {
        cout << x - r << " " << y << " " << x + r << " " << y << " " << x << " " << y0 + r;
        return;
    }
    double xa, xb, xc, ya, yb, yc, tmp;
    if (h < r / 2)
    {
        tmp = sqrt(r * r - h * h);
        bool xx = x0 > x;
        bool yy = y0 > y;
        bool pan = xx ^ yy;
        xa = x0 + tmp * sin(jiao);
        ya = y0 + pow(-1, pan + 1) * tmp * cos(jiao);
        xb = x0 - tmp * sin(jiao);
        yb = y0 - pow(-1, pan + 1) * tmp * cos(jiao);
        if (y - y0 <= 5e-7)
            xx |= 1;
        if (x - x0 <= 5e-7)
            yy |= 1;
        xc = x + pow(-1, xx) * r * cos(jiao);
        yc = y + pow(-1, yy) * r * sin(jiao);
        cout << fixed << setprecision(9) << xa << " " << ya << " " << xb << " " << yb << " " << xc << " " << yc;
    }
    else
    {
        double ax, ay;
        tmp = sqrt(3) / 2 * r;
        bool xx = x0 > x;
        bool yy = y0 > y;
        bool pan = xx ^ yy;
        if (xx)
            ax = x + r * cos(jiao) / 2;
        else
            ax = x - r * cos(jiao) / 2;
        if (yy)
            ay = y + r * sin(jiao) / 2;
        else
            ay = y - r * sin(jiao) / 2;
        xa = ax + tmp * sin(jiao);
        ya = ay + pow(-1, pan + 1) * tmp * cos(jiao);
        xb = ax - tmp * sin(jiao);
        yb = ay - pow(-1, pan + 1) * tmp * cos(jiao);
        if (y - y0 <= 5e-7)
            xx |= 1;
        if (x - x0 <= 5e-7)
            yy |= 1;

        xc = x + pow(-1, xx) * r * cos(jiao);
        yc = y + pow(-1, yy) * r * sin(jiao);
        cout << fixed << setprecision(9) << xa << " " << ya << " " << xb << " " << yb << " " << xc << " " << yc;
    }

    // cerr << xa << " " << ya << endl;
    // cerr << xb << " " << yb << endl;
    // cerr << xc << " " << yc;
}
signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr), cout.tie(nullptr);
    int awa = 1;
    // cin >> awa;
    while (awa--)
    {
        _();
    }
    return 0;
}