20B - Equation - CodeForces Solution

#include <bits/stdc++.h>
#include <cstring>
#include <math.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double db;
//typedef double db;
#define ss second
#define ff first
#define pb push_back
#define vi vector<int>
#define pii pair<int,int>
#define vii vector<pii>
#define vl vector<ll>
#define pll pair<ll,ll>
#define vll vector<pll>
#define vd vector<db>
#define pdd  pair<db,db>
#define vdd  vector<pdd>
#define mll map <ll,ll>
#define sl set <ll>
#define sll set <pll>
#define f(i,j,k,l) for(ll i=j;i<k;i+=l)
#define fj(j,m) for(auto j=m.begin();j!=m.end();j++)
#define yes cout<<"YES"<<endl;
#define no cout<<"NO"<<endl;
#define endl "\n"
const db pi=3.14159265359;
const int mod = 1e9+7;
const db EPS = 0.000000001; // 1 e -9
const ll inf = (ll)1e18;
ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;}
ll lcm(ll a , ll b) {return (a * b) / gcd(a , b);}

int run_case()
{
    ll  r,k,u,p,i,n,h,y,z,l,e,q,w,x,j;
    cin >> k >> n >> x ;
    cout << setprecision(5) << fixed;
    if (k==0)
    {
        if (n==0)
        {
            if (x==0)
            {
                cout << -1 << endl;
            }
            else
            {
                cout << 0 << endl;
            }
        }
        else
        {
            cout << 1 << endl;
            cout << -(db)x/(db)n << endl;
        }
    }
    else
    {
        p=n*n-4*k*x;
        if (p>0)
        {
            cout << 2 << endl;
            cout << min((-(db)n-sqrt(p))/(2.0*k),(-(db)n+sqrt(p))/(2.0*k)) << endl;
            cout << max((-(db)n+sqrt(p))/(2.0*k),(-(db)n-sqrt(p))/(2.0*k)) << endl;
        }
        else if (p==0)
        {
            cout << 1 << endl;
            cout << -(db)n/(2.0*k) << endl;
        }
        else
        {
            cout << 0 << endl;
        }
    }

return 0;
}
int main()
{
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    ll t = 1;//cin >> t;
    while(t--){
        run_case();
    }
    return 0;
}