Quicksort facts for kids
Imagine you have a messy pile of things, like a stack of homework papers or a list of numbers, and you want to put them in order. Quicksort is a clever method, or algorithm, that computers use to sort these items very quickly. It was invented by a smart person named Tony Hoare in 1959. Even today, it's one of the most popular ways computers sort information.
Quicksort works by picking one item, called a pivot, and then moving all smaller items to one side of it and all larger items to the other side. It keeps doing this until everything is perfectly sorted.
How Quicksort Works
Quicksort uses a trick called "divide and conquer." This means it breaks a big problem into smaller, easier-to-solve pieces. Here are the steps it follows:
- Step 1: Choose a Pivot
First, Quicksort picks one item from the list. This item is called the pivot. Think of it like a dividing line. Often, the first or last item in the list is chosen as the pivot.
- Step 2: Arrange Around the Pivot
Next, the algorithm looks at every other item in the list. * If an item is smaller than the pivot, it moves to the left side of the pivot. * If an item is larger than the pivot, it moves to the right side of the pivot. After this step, the pivot item is in its final, correct sorted spot! All items to its left are smaller, and all items to its right are larger.
- Step 3: Sort the Smaller Parts
Now, Quicksort takes the group of items to the left of the pivot (the smaller ones) and does the exact same steps again. It picks a new pivot in that smaller group and arranges items around it.
- Step 4: Sort the Larger Parts
It also takes the group of items to the right of the pivot (the larger ones) and repeats the same steps. It picks a new pivot in that group and arranges items.
This process is called recursion. It means the algorithm keeps calling itself on smaller and smaller parts of the list. It stops when a part of the list has only one item, because a single item is already sorted! By repeating these steps, Quicksort eventually puts every item in its correct place.
See also
In Spanish: Quicksort para niños
