Bubble Sort

Core idea

The algorithm walks through the array many times. On each pass, it compares adjacent values and swaps them if the left value is greater than the right one.

Large values gradually “bubble” to the right edge, so after every pass the last unsorted position becomes fixed.

Bubble Sort is easy to understand, but inefficient on large inputs, which makes it a good teaching example rather than a practical production sort.

// Проходим все элементы массива и меняем соседей местами,
// если хоть одна смена за цикл произошла, то запускаем еще одну итерацию по флагу.
// Каждая новая итерация меньше предыдущей на один.
// O(n^2)

function bubbleSort (arr) {
 let swapped = false;
 let count = 0;
 do {
   swapped = false;
   for (let i = 0; i < arr.length - 1 - count; i++) {
     if (arr[i+1] < arr[i]) {
       const tmp = arr[i+1];
       arr[i+1] = arr[i];
       arr[i] = tmp;
       swapped = true;
     }
   }
   count++;
 } while (swapped === true)
 return arr;
}