solution0052.js

/*
--------------- 7  Kyu - You're a square! ------------------

Instructions:

A square of squares
You like building blocks. You especially like building blocks that are squares. And what you even like more, is to arrange them into a square of square building blocks!

However, sometimes, you can't arrange them into a square. Instead, you end up with an ordinary rectangle! Those blasted things! If you just had a way to know, whether you're currently working in vain… Wait! That's it! You just have to check if your number of building blocks is a perfect square.

Task
Given an integral number, determine if it's a square number:

In mathematics, a square number or perfect square is an integer that is the square of an integer; in other words, it is the product of some integer with itself.

The tests will always use some integral number, so don't worry about that in dynamic typed languages.

Examples
-1  =>  false
 0  =>  true
 3  =>  false
 4  =>  true
25  =>  true
26  =>  false

-------------
Sample Tests

describe("isSquare", function(){
  it("should work for some examples", function(){
    Test.assertEquals(isSquare(-1), false, "-1: Negative numbers cannot be square numbers");
    Test.assertEquals(isSquare( 0), true, "0 is a square number (0 * 0)");
    Test.assertEquals(isSquare( 3), false, "3 is not a square number");
    Test.assertEquals(isSquare( 4), true, "4 is a square number (2 * 2)");
    Test.assertEquals(isSquare(25), true, "25 is a square number (5 * 5)");
    Test.assertEquals(isSquare(26), false, "26 is not a square number");
  });
});

--------------

Psuedo Code:


-use Math.sqrt() to determine if number is a square number/perfect square
-if result is an integer, return true
-if result is a float, return false
-determine if result is integer or float by use of % 1 (num % 1 = 0 is an integer; num % 1 = anything else and it's a float)

Lessons Learned:
-I tried to write this more concisely, without the true : false expression. Turns out this was possible, but I needed to also discard the ternary, and possibly use a strict equality operator instead
*/

var isSquare = function(n){
    return Math.sqrt(n) % 1 == 0 ? true : false
  }