Skip to content

Commit

Permalink
feat: insertion sort with binary search (TheAlgorithms#1182)
Browse files Browse the repository at this point in the history
  • Loading branch information
syedjafer_k authored Oct 16, 2022
1 parent 8c847e3 commit 18baef8
Show file tree
Hide file tree
Showing 2 changed files with 68 additions and 0 deletions.
60 changes: 60 additions & 0 deletions Sorts/BinaryInsertionSort.js
Original file line number Diff line number Diff line change
@@ -0,0 +1,60 @@
/**
* Pure Implementation of Binary Search Algorithm
*
* Binary insertion sort is a sorting algorithm similar to insertion sort,
* but instead of using linear search to find the position
* where the element should be inserted, we use binary search.
* Thus, we reduce the number of comparisons for inserting one element from O(N)
* (Time complexity in Insertion Sort) to O(log N).
*
*/

/**
* Search the key element in the array from start position to end position.
*
* @param {Array} array Array of numbers.
* @param {Number} key Value to be searched
* @param {Number} start start index position of array
* @param {Number} end end index position of array
* @return {Number} Position of the key element
*/
function binarySearch (array, key, start, end) {
if (start === end) {
if (array[start] > key) {
return start
} else {
return start + 1
}
}

if (start > end) {
return start
}

const mid = Math.floor((start + end) / 2)

if (array[mid] < key) {
return binarySearch(array, key, mid + 1, end)
} else if (array[mid] > key) {
return binarySearch(array, key, start, mid - 1)
} else {
return mid
}
}

/**
* Binary Insertion Sort
*
* @param {Array} list List to be sorted.
* @return {Array} The sorted list.
*/
export function binaryInsertionSort (array) {
const totalLength = array.length
for (let i = 1; i < totalLength; i += 1) {
const key = array[i]
const indexPosition = binarySearch(array, key, 0, i - 1)
array.splice(i, 1)
array.splice(indexPosition, 0, key)
}
return array
}
8 changes: 8 additions & 0 deletions Sorts/test/BinaryInsertionSort.test.js
Original file line number Diff line number Diff line change
@@ -0,0 +1,8 @@
import { binaryInsertionSort } from '../BinaryInsertionSort'

describe('BinaryInsertionSort', () => {
it('should sort arrays correctly', () => {
expect(binaryInsertionSort([5, 4, 3, 2, 1])).toEqual([1, 2, 3, 4, 5])
expect(binaryInsertionSort([7, 9, 4, 3, 5])).toEqual([3, 4, 5, 7, 9])
})
})

0 comments on commit 18baef8

Please sign in to comment.