math

问题 In java, I know the data type of the result of an arithmetic calculation depends on the data types of the numbers involved in the calculation. For example, int + int = int long/double=double a. But I can't find any references which can give me all these rules. Could someone help me? b. How to avoid over flow in arithmetic calculation? For example, the results of 2 long may not fit into a long anymore... Thanks a lot. 回答1: a. These rules are called numeric promotion rules and are specified in

问题 I have the following code which determines whether a number is prime: public static boolean isPrime(int n){ boolean answer = (n>1)? true: false; for(int i = 2; i*i <= n; ++i) { System.out.printf("%d\n", i); if(n%i == 0) { answer = false; break; } } return answer; } How can I determine the big-O time complexity of this function? What is the size of the input in this case? 回答1: Think about the worst-case runtime of this function, which happens if the number is indeed prime. In that case, the

问题 0/10 test cases are passing. Here is the challenge description: (to keep formatting nice - i put the description in a paste bin) Link to challenge description: https://pastebin.com/UQM4Hip9 Here is my trial code - PYTHON - (0/10 test cases passed) from math import factorial from collections import Counter from fractions import gcd def cycle_count(c, n): cc=factorial(n) for a, b in Counter(c).items(): cc//=(a**b)*factorial(b) return cc def cycle_partitions(n, i=1): yield [n] for i in range(i,

问题 UPDATE as on 12 Nov 2015 I used PanoTools plugin with Photoshop and Hugin and played with all those parameters. End up i found the parameters for projection, HFOV and image output size that fulfill my lowest requirement. Parameteres: Processed Output: My question is then how can i convert all these parameters and values into C# algorithm coding so that when I provide the original image, i will get the corrected output image? Thanks a lot. I have a square image captured from a circular fisheye

问题 UPDATE as on 12 Nov 2015 I used PanoTools plugin with Photoshop and Hugin and played with all those parameters. End up i found the parameters for projection, HFOV and image output size that fulfill my lowest requirement. Parameteres: Processed Output: My question is then how can i convert all these parameters and values into C# algorithm coding so that when I provide the original image, i will get the corrected output image? Thanks a lot. I have a square image captured from a circular fisheye

问题 I have created a class for complex numbers: public class Complex { private double x; //Real part x of the complex number x+iy. private double y; //Imaginary part y of the complex number x+iy. public Complex(double x, double y) { //Constructor: Initializes x, y. this.x=x; this.y=y; } public Complex(double x) { //Real constructor - initialises with a real number. this(x, 0.0); } public Complex() { //Default constructor; initialiase x and y to zero. this(0.0, 0.0); } } What I would like to do is

问题 I am a beginner at C#. I am facing a problem while converting a string to a mathematical expression. I have a UI where user can create formula using random formula field. And in another UI user will give input of those formula field. like for example at first time the formula may be (a+b)^n and another the formula may be ((a+b+c)^n+b) . In my calculation UI for the first time user will give input for a,b,n and for 2nd formula user will give input for a,b,c,n. Can anyone please help me about

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: How do you round to 1 decimal place in Javascript? The following code, displays the total distance covered, on a particular route, displayed on google maps. I managed to convert the number from kilometers to miles. Here is the code for the function: function computeTotalDistance(result) { var total = 0; var myroute = result.routes[0]; for (i = 0; i < myroute.legs.length; i++) { total += myroute.legs[i].distance

问题 if you are to choose a random a 512-bit integer N that is not a multiple of 2, 3, or 5 What is the probability that N is prime? i don't know the algorithm behind this one... i'm trying to work on a project but this is the starting point.. :) 回答1: The number of primes less than n=2 512 is approximately n/log(n). The number of numbers you are considering is 4/15*n, so the probability you are looking for is 15/(4*log(n)), which is about 1 %. 回答2: Probability bounds You may use the following

问题 Attempting to control orthorgraphic camera position (x,y,z) and up vector (top of camera) from euler angles. I have a real world device with an IMU that outputs rotation along each axis (x,y,z). I'm trying to translate these angles into camera eye position and up vector direction. If the physical device is altered, the change in orientation should be reflected in the change in position of the camera. I'm having a hard time with the math behind this mapping, and have not had a ton of luck in