What is the fastest way to XOR two integers in C #?

I need an XOR one integer aversus an array of integers q(max 100,000). that is, if I go in cycles, I will

a XOR q [0]

a XOR q [1]

.....

a XOR q [100000]

(100,000 times)

I will have a series of such afor XORed.

I am writing a console application that will pass the required input.

I use the built-in C # operator ^to perform the XOR operation. Is there another way?

Would converting an integer to an array of bytes and then XORing each bit and determining the final result is a good idea?

Input (do not keep spaces between two lines)

1

15 8

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

10 6 10

1023 7 7

33 5 8

182 5 10

181 1 13

5 10 15

99 8 9

33 10 14

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace XOR
{
    class Solution
    {
        static void Main(string[] args)
        {

            List<TestCase> testCases = ReadLine();
            //Console.WriteLine(DateTime.Now.ToLongTimeString());
            CalculationManager calculationManager = new CalculationManager();

            foreach (var testCase in testCases)
            {
                var ints = testCase.Queries.AsParallel().Select(query => calculationManager.Calculate(query, testCase.SequenceOfIntegers)).ToList();
                ints.ForEach(Console.WriteLine);
            }

            //Console.WriteLine(DateTime.Now.ToLongTimeString());
            //Console.ReadLine();
        }

        private static List<TestCase> ReadLine()
        {
            int noOfTestCases = Convert.ToInt32(Console.ReadLine());
            var testCases = new List<TestCase>();

            for (int i = 0; i < noOfTestCases; i++)
            {
                string firstLine = Console.ReadLine();
                string[] firstLineSplit = firstLine.Split(' ');
                int N = Convert.ToInt32(firstLineSplit[0]);
                int Q = Convert.ToInt32(firstLineSplit[1]);

                var testCase = new TestCase
                                   {
                                       Queries = new List<Query>(),
                                       SequenceOfIntegers = ReadLineAndGetSequenceOfIntegers()
                                   };

                for (int j = 0; j < Q; j++)
                {
                    var buildQuery = ReadLineAndBuildQuery();
                    testCase.Queries.Add(buildQuery);
                }

                testCases.Add(testCase);
            }

            return testCases;
        }

        private static List<int> ReadLineAndGetSequenceOfIntegers()
        {
            string secondLine = Console.ReadLine();
            List<int> sequenceOfIntegers = secondLine.Split(' ').ToArray().Select(x => Convert.ToInt32(x)).ToList();
            return sequenceOfIntegers;
        }

        private static Query ReadLineAndBuildQuery()
        {
            var query = Console.ReadLine();
            List<int> queryIntegers = query.Split(' ').ToArray().Select(x => Convert.ToInt32(x)).ToList();
            Query buildQuery = ReadLineAndBuildQuery(queryIntegers[0], queryIntegers[1], queryIntegers[2]);
            return buildQuery;
        }

        private static Query ReadLineAndBuildQuery(int a, int p, int q)
        {
            return new Query { a = a, p = p, q = q };
        }


    }

    class CalculationManager
    {
        public int Calculate(Query query, List<int> sequenceOfIntegers)
        {
            var possibleIntegersToCalculate = FindPossibleIntegersToCalculate(sequenceOfIntegers, query.p, query.q);
            int maxXorValue = possibleIntegersToCalculate.AsParallel().Max(x => x ^ query.a);
            return maxXorValue;
        }

        private IEnumerable<int> FindPossibleIntegersToCalculate(List<int> sequenceOfIntegers, int p, int q)
        {
            return sequenceOfIntegers.GetRange(p - 1, (q - p) + 1).Distinct().ToArray();
        }
    }

    class TestCase
    {
        public List<int> SequenceOfIntegers { get; set; }
        public List<Query> Queries { get; set; }
    }

    class Query
    {
        public int a { get; set; }
        public int p { get; set; }
        public int q { get; set; }
    }
}
+5
source
4

xor- ^ xor.

.

:

        int i = 4;
00000029  mov         dword ptr [ebp-3Ch],4 
        i ^= 3;
00000030  xor         dword ptr [ebp-3Ch],3 

, , , / ( ), xor.

+16

, ( , int ), unsafe int[] long* 64- ( , ^) 32, . IIRC, , - ( - "-" - XOR). , .

+5

xor , ( ) , :

int x = q[0]
for(int i = 1; i < q.Length; i++)
   x ^= q[i]

a1 ^= x
a2 ^= x
...

EDIT:   , .

int x = a1 ^ a2 ^ ... an
for(int i = 0; i < q.Length; i++)
     q[i] ^= x
0

XOR - , , .

, , xor .

eg. if you read integers from a text file. The io + disk parsing time will be several times larger than the xor time. The operating system will also be used read-ahead, which in practice means that it selects the next batch of integers when processing the current batch. This means that parsing + xor does not add extra time to the total processing time, except for the last batch.

0
source

All Articles