I had an interesting job interview experience a while back. The question started really easy: Q1: We have a bag containing numbers 1, 2, 3, …, 100. Each number appears exactly once, so there are 100 numbers. Now one number is randomly picked out of the bag. Find the missing number. I’ve heard this interview … Read more
float(‘nan’) represents NaN (not a number). But how do I check for it? 1 18 Use math.isnan: Return True if x is a NaN (not a number), and False otherwise. >>> import math >>> x = float(‘nan’) >>> math.isnan(x) True
Given two date ranges, what is the simplest or most efficient way to determine whether the two date ranges overlap? As an example, suppose we have ranges denoted by DateTime variables StartDate1 to EndDate1 and StartDate2 to EndDate2. 3 36
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 … Read more
Consider the following code: 0.1 + 0.2 == 0.3 -> false 0.1 + 0.2 -> 0.30000000000000004 Why do these inaccuracies happen? 3 31
You are multiplying ints together, and overflow occurs because the maximum integer is 2^31 – 1. Only after the multiplications does it get converted to a long. Cast the first number as a long. long days_30 = (long) 1000 * 60 * 60 * 24 * 30; or use a long literal: long days_30 = … Read more
No, Math.ceil() won’t work on its own because the problem occurs earlier. a and b are both integers, so dividing them evaluates to an integer which is the floor of the actual result of the division. For a = 3 and b = 2, the result is 1. The ceiling of one is also one – hence you won’t get the desired result. You must … Read more
What is the best math library to use with java?
Inverse Logistic Function / Reverse Sigmoid Function
Converting the output is too late; the calculation has already taken place in integer arithmetic. You need to convert the inputs to double: System.out.println((double)completed/(double)total); Note that you don’t actually need to convert both of the inputs. So long as one of them is double, the other will be implicitly converted. But I prefer to do both, for symmetry.
