In-place Algorithm to Move Zeros to End of List in JavaScript

Suppose we are given an array of integers, lets say arr. We are required to write a function that puts all the zeros to the back of the array by modifying the list in-place.

The function should do this in such a way that the relative ordering of other elements should stay the same.

For example −

If the input array is −

const arr = [0, 11, 0, 22, 67];

Then the array should be modified to −

const output = [11, 22, 67, 0, 0];

Example

Following is the code −

const arr = [0, 11, 0, 22, 67];
const moveZeroToEnd = (arr = []) => {
   const swap = (array, ind1, ind2) => {
      const temp = array[ind1];
      array[ind1] = array[ind2];
      array[ind2] = temp;
   };
   let j = 0;
   for (let i = 0; i < arr.length; ++ i) {
      if (arr[i] !== 0) {
         swap(arr, i, j++);
      }
   }
   while (j < arr.length) {
      arr[j++] = 0;
   };
};
moveZeroToEnd(arr);
console.log(arr);

Output

Following is the console output −

[11, 22, 67, 0, 0]