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What is Simple Selection Method (Selection Sort)?
Selection sort is a commonly used sorting algorithm in computer science. It is a simple comparison-based sorting algorithm that works by repeatedly finding the minimum element from an unsorted part of the array and placing it at the beginning of the sorted part.
Explanation of the Algorithm:
1. Start by dividing the array into two parts: the sorted part at the beginning, and the unsorted part at the end. Initially, the sorted part is empty, and the unsorted part contains the entire array.
2. Find the minimum element in the unsorted part of the array. This can be done by iterating through the unsorted part and comparing each element with the minimum found so far.
3. Swap the minimum element with the first element of the unsorted part. This moves the minimum element to the sorted part of the array, and reduces the size of the unsorted part by one.
4. Repeat steps 2 and 3 until the unsorted part becomes empty. This will result in a sorted array.
The selection sort algorithm works by iteratively selecting the minimum element from the unsorted part and placing it at the correct position in the sorted part. This process is repeated until the entire array is sorted.
Example:
Let’s consider the following array: [5, 3, 2, 4, 1]
1. Initially, the sorted part is empty, and the unsorted part contains the entire array: [5, 3, 2, 4, 1]
2. The minimum element in the unsorted part is 1. Swap it with the first element: [1, 3, 2, 4, 5]
3. Now, the sorted part contains the minimum element. Repeat the process for the remaining unsorted part: [1, 2, 3, 4, 5]
4. The unsorted part is empty, and the array is now sorted.
Time Complexity:
The time complexity of the selection sort algorithm is O(n^2), where n is the number of elements in the array. This is because for every element in the array, it needs to iterate through the remaining unsorted part to find the minimum element.
In practical scenarios, selection sort is not efficient for large datasets because of its quadratic time complexity. However, it can be useful for small datasets or when the array is almost sorted.
This algorithm serves as a good introduction to sorting algorithms and can be used as a stepping stone for understanding more complex and efficient sorting algorithms.
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