AcWing 790. 数的三次方根

题目连接

https://www.acwing.com/problem/content/792/

思路

浮点二分没啥好说的，迭代到一个零界点即可

代码

#include
using namespace std;
#define ll long long
#define mod 1000000009
#define endl "\n"
#define PII pair
ll ksm(ll a,ll b) {
	ll ans = 1;
	for(;b;b>>=1LL) {
		if(b & 1) ans = ans * a % mod;
		a = a * a % mod;
	}
	return ans;
}

ll lowbit(ll x){return -x & x;}

const int N = 2e6+10;
#define EPS 1e-8

double n;

bool check(double x) {
	if(x * x * x  EPS) {
		double mid = (l + r) / 2.0;
		if(check(mid)) l = mid;
		else r = mid;
	}
	printf("%lf\n",r);
	
	return 0;
}