牛顿迭代法
class Solution {
public double mySqrt (int c) {
double err = 1e-9;
double x0 = 0;
double x1 = c;
while(true){
x0 = 0.5*x1+0.5*c/x1;
if(Math.abs(x1 - x0) < err){
break;
}
x1 = x0;
}
return x1;
}
}
// String.format("%.2f",x1); 保留到小数点后两位