On the operator ^ problem

topic description

given a sequence containing n numbers of 0, 1, 2,., n, find 0. The number in n that does not appear in the sequence.

related codes 

var missingNumber = function(nums) {
    var res = nums.length;
    
    for(var i = 0; i < nums.length; iPP){
        res = res^(i ^ nums[i]);
    }
    
    return res;
};

see a great god"s answer, but do not quite understand the meaning of res = res ^ (I ^ nums [I]); , check the explanation of ^, debug the program, still do not quite understand how to compare it, please answer, thank you

Javascript
Mar.30,2022

Bitwise_Operators-sharp 

var missingNumber = function(nums) {
    var res = nums.length;
    
    for(var i = 0; i < nums.length; iPP){
        res = res^(i ^ nums[i]);
    }
    
    return res;
};

first of all, XOR does not need to control the order.
assume that the array is a continuous [1meme2... code n] array, then nums.length must be equal to some value in the array, that is, n ^ nums.length is 0 , because x ^ 0 is x , so if the data is continuous, there must be nFel.1 with the same logic as the appeal process.

The final result is length XOR each value XOR subscript , that is, 3 ^ 3 ^ 2 ^ 0 ^ 2 .

PS: personal use of such code is not recommended

has two main properties:

  1. XOR satisfies the commutative law;
  2. two bits XOR, 0 if the same, 1 if the difference.

simplify the problem, for example, given the array [0, 1, 2, 3, 5], it is missing a 4, and now we need to find 4. 

  https://subetter.com/articles.... 


 A bit more powerful, refer to the book "algorithms to learn the Mysteries of efficient algorithms", which is almost out of print and brain-burning.

Previous: Python2.7 reads sqlserver database to burst memory

Next: Is the file uploaded by the browser transferred in bytes (serialized? )?

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1e5986b-44017.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1e5986b-44017.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?