VietMX Staff asked 4 years ago
Bubble Sort is based on the idea of repeatedly comparing pairs of adjacent elements and then swapping their positions if they are in the wrong order. Bubble sort is a stable, in-place sort algorithm.
How it works:
- In an unsorted array of
nelements, start with the first two elements and sort them in ascending order. (Compare the element to check which one is greater). - Compare the second and third element to check which one is greater, and sort them in ascending order.
- Compare the third and fourth element to check which one is greater, and sort them in ascending order.
- …
- Repeat steps 1–
nuntil no more swaps are required.
Visualisation:
Complexity Analysis
Bubble sort has a worst-case and average complexity of O(n2), where n is the number of items being sorted. When the list is already sorted (best-case), the complexity of bubble sort is only O(n). The space complexity for Bubble Sort is O(1), because only single additional memory space is required (for temp swap element).
Implementation
// Normal
const bubbleSort = function(array) {
let swaps;
do {
swaps = false;
for (let i = 0; i < array.length - 1; i++) {
if (array[i] > array[i + 1]) {
let temp = array[i + 1];
array[i + 1] = array[i];
array[i] = temp;
swaps = true;
}
}
} while (swaps);
return array;
};
// Recursively
const bubbleSort = function (array, pointer = array.length - 1) {
// Base Case
if (pointer === 0) {
return array;
}
for (let i = 0; i < pointer; i++) {
if (array[i] > array[i + 1]) {
let temp = array[i + 1];
array[i + 1] = array[i];
array[i] = temp;
}
}
// Recursive call on smaller portion of the array
return bubbleSort(array, pointer - 1);
};