xor

Given an array of integers ,You have to find two elements whose XOR is maximum. There is naive approach --just by picking each element and xoring with other elements and then comparing the results to find the pair. Other than this ,Is there any efficient algorithm? templatetypedef I think I have an O(n lg U) algorithm for this, where U is the largest number. The idea is similar to user949300's, but with a bit more detail. The intuition is as follows. When you're XORing two numbers together, to get the maximum value, you want to have a 1 at the highest possible position, and then of the

I'm trying to encrypt/decrypt a file using XOR. I have the following encryption/decryption routine where every byte is xor'd and the result is being subtracted by the value of the byte that is located at the previous location. The ASM representation is as follows crypt: mov dl, [eax+ecx] ; read byte xor dl, 0C5h ; xor it with oxC5 sub dl, [eax+ecx-1] ; sub the previous byte mov [eax+ecx], dl ; save the new byte dec eax ; decrement pointer test eax, eax jg short crypt ; That is what my encryption routine should look like, I'm trying to port this this C/C++. My code is as follows #include <stdio

Random randgen = new Random(); int dkey; public object SetScore(int val) { dkey=randgen.Next(int.MaxValue/2); return val ^ dkey; //^ means XOR. } public string GetScore(int val) { return val ^ dkey; GC.Collect(); } From public string GetScore(int val) { return val ^ dkey; GC.Collect(); } the return val ^ dkey shows the error Cannot implicitly convert type 'int' to 'string' Your GetScore method returns a string, but val ^ dkey is an integer. Either convert the result to string with: return (val ^ dkey).ToString(); or return an int: public int GetScore(int val) ... Oh, and please remove the call

From time to time we have to analyze pieces of assembler code (IA32), and more than often i come across an instruction that looks like this: xor ax, ax or with other registers aswell: xor dx, dx , xor al, al , ... What exactly does this do ? (ax xor ax always gives 0 ?) It's a common assembler idiom to set a register to 0. xor ax, ax corresponds to ax = ax ^ ax which, as you already notices, is effectively ax = 0 . If I recall correctly the main advantage is that its code-size is smaller than mov ax, 0 That is exactly what it does -- zero the contents of a register xor %ax, %ax, as stated in

I'm trying to xor 2 binaries using python like this but my output is not in binary any help? a = "11011111101100110110011001011101000" b = "11001011101100111000011100001100001" y = int(a) ^ int(b) print y a = "11011111101100110110011001011101000" b = "11001011101100111000011100001100001" y = int(a,2) ^ int(b,2) print '{0:b}'.format(y) BigH To get the Xor'd binary to the same length, as per the OP's request, do the following: a = "11011111101100110110011001011101000" b = "11001011101100111000011100001100001" y = int(a, 2)^int(b,2) print bin(y)[2:].zfill(len(a)) [output:

I have written following function to find if one and only one of 5 variables is true: (define (oneof v w x y z) (or (and v (not w) (not x) (not y) (not z)) (and w (not v) (not x) (not y) (not z)) (and x (not v) (not w) (not y) (not z)) (and y (not v) (not w) (not x) (not z)) (and z (not v) (not w) (not x) (not y)) )) (xor takes only 2 arguments) However, it is very imperative and not functional. Moreover, I want to write a function (oneof N) which will be generic rather than specific for 5 variables. How can this be done? Thanks. Edit: As pointed out in the comments, the code is 'repetitive'

I was just wondering if there is an XOR logical operator in C (something like && for AND but for XOR). I know I can split an XOR into ANDs, NOTs and ORs but a simple XOR would be much better. Then it occurred to me that if I use the normal XOR bitwise operator between two conditions, it might just work. And for my tests it did. Consider: int i = 3; int j = 7; int k = 8; Just for the sake of this rather stupid example, if I need k to be either greater than i or greater than j but not both, XOR would be quite handy. if ((k > i) XOR (k > j)) printf("Valid"); else printf("Invalid"); or printf("%s"