Question

How to find the number occurring an odd number of times in an array with JavaScript

Answer 1

function get_number_that_occurring_an_odd_number_of_times_in_array(arr) {
    const size = arr.length;
    let value = 0; 
    
    for (let i = 0; i < size; i++) {
        value ^= arr[i];
    }
    
    for (let i = 0; i < size; i++) {
        if (arr[i] == value) {
            return value;
        }
    }

    return -1;
}

         
const arr = [1, 1, 2, 2, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5];
         
console.log(get_number_that_occurring_an_odd_number_of_times_in_array(arr));

   
/*
run:
   
3
   
*/

 

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