# Special type of sorting algorithm in JavaScript

JavascriptWeb DevelopmentFront End Technology

#### JavaScript for beginners

Best Seller

74 Lectures 10 hours

#### Modern Javascript for Beginners + Javascript Projects

Most Popular

112 Lectures 15 hours

#### The Complete Full-Stack JavaScript Course!

Best Seller

96 Lectures 24 hours

We are required to write a JavaScript function that takes in an array of integers as the only argument.

The function should sort the array based on the following conditions −

• All even numbers are sorted in increasing order

• All odd numbers are sorted in decreasing order

• The relative positions of the even and odd numbers remain the same

For example −

If the input array is −

const arr = [12, 17, 15, 24, 1, 6];

Then the output should be −

const output = [6, 17, 15, 12, 1, 24];

## Example

Following is the code −

const arr = [12, 17, 15, 24, 1, 6];
const specialSort = (nums = []) => {
const oddArr = [], evenArr = [];
for (let i = 0; i < nums.length; i++){
if (nums[i] & 1) {
oddArr.push(i);
} else {
evenArr.push(i);
}
}
nums.sort((a, b) => a - b);
let odd = oddArr.length - 1, even = 0;
const res = [];
for (let i = 0; i < nums.length; i++){
if (nums[i] & 1) {
res[oddArr[odd--]] = nums[i];
} else {
res[evenArr[even++]] = nums[i];
}
}
return res;
}

## Output

Following is the console output −

[ 6, 17, 15, 12, 1, 24 ]
Updated on 22-Jan-2021 07:05:11