Language: C++

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep1(i, n) for (int i = 1; i <= (int)(n); i++)
/* ------------------------------------------------ */
ll fact(int i) {       //階乗
    if (i == 0) return 1;
    return (fact(i - 1)) * i;
}
ll gcd(ll a, ll b) {        //最大公約数
    if(b == 0) return a;
    return gcd(b, a % b); 
}
ll lcm(ll a, ll b) {      //最小公倍数
    return a * b / gcd(a, b);
}
int keta(ll n) {        //桁数を求める
    if(n == 0) return 1;
    int count = 0;
    while(n != 0) {
        n /= 10;
        count++;
    }
    return count;
}
ll ketasum(ll n) {    //各桁の和
    ll sum = 0;
    while(n != 0) {
        sum += n % 10;
        n /= 10;
    }
    return sum;
}
/* ------------------------------------------------ */
int main() {
    long double a, b, c;
    cin >> a >> b >> c;
    ll k = gcd(a, gcd(b, c));
    a /= k;
    b /= k;
    c /= k;
    // 2 * sqrt(a * b) < c - a - b ? cout << "Yes" << endl : cout << "No" << endl;
    // sqrt(a) + sqrt(b) < sqrt(c) ? cout << "Yes" << endl : cout << "No" << endl;
    // cout << sqrt(2) << endl;
    4 * a * b < c * c + a * a + b * b + 2 * (a * b - b * c - c * a ) ? cout << "Yes" << endl : cout << "No" << endl;
    return 0;
}

Compiler output:
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:58,
                 from a.cc:1:
/usr/include/c++/14/numeric: In instantiation of 'constexpr std::common_type_t<_Mn, _Nn> std::gcd(_Mn, _Nn) [with _Mn = long double; _Nn = long double; common_type_t<_Mn, _Nn> = long double]':
a.cc:39:22:   required from here
   39 |     ll k = gcd(a, gcd(b, c));
      |                   ~~~^~~~~~
/usr/include/c++/14/numeric:175:21: error: static assertion failed: std::gcd arguments must be integers
  175 |       static_assert(is_integral_v<_Mn> && is_integral_v<_Nn>,
      |                     ^~~~~~~~~~~~~~~~~~
/usr/include/c++/14/numeric:175:21: note: 'std::is_integral_v<long double>' evaluates to false
In file included from /usr/include/c++/14/bits/stl_pair.h:60,
                 from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/type_traits: In instantiation of 'struct std::make_unsigned<long double>':
/usr/include/c++/14/type_traits:2076:11:   required by substitution of 'template<class _Tp> using std::make_unsigned_t = typename std::make_unsigned::type [with _Tp = long double]'
 2076 |     using make_unsigned_t = typename make_unsigned<_Tp>::type;
      |           ^~~~~~~~~~~~~~~
/usr/include/c++/14/numeric:182:24:   required from 'constexpr std::common_type_t<_Mn, _Nn> std::gcd(_Mn, _Nn) [with _Mn = long double; _Nn = long double; common_type_t<_Mn, _Nn> = long double]'
  182 |       return __detail::__gcd<make_unsigned_t<_Ct>>(__m2, __n2);
      |              ~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:39:22:   required from here
   39 |     ll k = gcd(a, gcd(b, c));
      |                   ~~~^~~~~~
/usr/include/c++/14/type_traits:1929:13: error: invalid use of incomplete type 'class std::__make_unsigned_selector<long double, false, false>'
 1929 |     { using type = typename __make_unsigned_selector<_Tp>::__type; };
      |             ^~~~
/usr/include/c++/14/type_traits:1837:11: note: declaration of 'class std::__make_unsigned_selector<long double, false, false>'
 1837 |     class __make_unsigned_selector;
      |           ^~~~~~~~~~~~~~~~~~~~~~~~