I'm looking for the fastest way to determine if a long value is a perfect square (i.e. its square root is another integer). I've done it the easy way, by using the built-in Math.sqrt() function, but I'm wondering if there is a way to do it faster by restricting yourself to integer-only domain. Maintaining a lookup table is impratical (...
Closed as Exact Duplicate: Fastest way to determine if an integer’s square root is an integer What's a way to see if a number is a perfect square? bool IsPerfectSquare(long input) { // TODO } I'm using C# but this is language agnostic. Bonus points for clarity and simplicity (this isn't meant to be code-golf). Edit: T...
Can I rely on sqrt((float)a)*sqrt((float)a)==a or (int)sqrt((float)a)*(int)sqrt((float)a)==a to check whether a number is a perfect square? Why or why not? int a is the number to be judged. I'm using Visual Studio 2005. Edit: Thanks for all these rapid answers. I see that I can't rely on float type comparison. (If I wrote as a...