What is insertion sort in C++?

What is insertion sort in C++?

Insertion sort is a simple sorting algorithm that builds a sorted array one element at a time. It works by comparing each new element to the already sorted elements and inserting it into the correct position.

Can you show me a code example of insertion sort in C++?

Sure! Here's a basic implementation of insertion sort in C++:

#include <iostream>
using namespace std;

void insertionSort(int arr[], int n) {
    for (int i = 1; i < n; i++) {
        int key = arr[i];
        int j = i - 1;
        while (j >= 0 && arr[j] > key) {
            arr[j + 1] = arr[j];
            j--;
        }
        arr[j + 1] = key;
    }
}

int main() {
    int arr[] = {12, 11, 13, 5, 6};
    int n = sizeof(arr) / sizeof(arr[0]);
    insertionSort(arr, n);
    cout << "Sorted array: ";
    for (int i = 0; i < n; i++)
        cout << arr[i] << " ";
    return 0;
}

This code sorts an array using the insertion sort algorithm.

What is the time complexity of insertion sort?

The time complexity of insertion sort is O(n^2) in the average and worst cases, but it can be O(n) in the best case when the array is already sorted.

When should I use insertion sort?

Insertion sort is efficient for small data sets or when the array is nearly sorted. It's also useful when memory space is limited.