Hey @prerakvarshney12
First, suppose n is the shortest side of the triangle, m, k are other two sides. According to Pythagorean Theorem, we know n^2 + m ^2 = k ^2
just do a change k^2 - m ^2 = n ^2
futherly ( k + m )( k - m ) = n^2
as we know, n ^2 × 1 = n ^2 so we can suppose that k + m = n ^2, k - m = 1
easily, we get 
because the side is a interger, so this solution can only be used when n is a odd.
So how to deal with even? we find that if (k-m) is odd, the solution is suitable for odd. On the other hand, we guess that if(k-m) is even, the solution is suitable for even.
just as this, 
so, we get 
this is an O (1) algorithm.