What are some examples of algorithms in C++?

What are some examples of algorithms in C++?

There are many algorithms in C++, such as sorting algorithms (like quicksort and mergesort), searching algorithms (like binary search), and graph algorithms (like Dijkstra's algorithm). Would you like to know more about a specific one?

Can you explain how quicksort works?

Sure! Quicksort is a divide-and-conquer algorithm. It works by selecting a 'pivot' element from the array and partitioning the other elements into two sub-arrays, according to whether they are less than or greater than the pivot. The sub-arrays are then sorted recursively.

What is the time complexity of quicksort?

The average time complexity of quicksort is O(n log n), but in the worst case, it can be O(n²) if the pivot elements are poorly chosen.

Can you provide a simple C++ code example for quicksort?

Certainly! Here's a simple implementation of quicksort in C++:

#include <iostream>
using namespace std;

void quicksort(int arr[], int low, int high) {
    if (low < high) {
        int pivot = partition(arr, low, high);
        quicksort(arr, low, pivot - 1);
        quicksort(arr, pivot + 1, high);
    }
}

int partition(int arr[], int low, int high) {
    int pivot = arr[high];
    int i = (low - 1);
    for (int j = low; j < high; j++) {
        if (arr[j] < pivot) {
            i++;
            swap(arr[i], arr[j]);
        }
    }
    swap(arr[i + 1], arr[high]);
    return (i + 1);
}

int main() {
    int arr[] = {10, 7, 8, 9, 1, 5};
    int n = sizeof(arr) / sizeof(arr[0]);
    quicksort(arr, 0, n - 1);
    cout << "Sorted array: ";
    for (int i = 0; i < n; i++)
        cout << arr[i] << " ";
    return 0;
}

This code sorts an array using the quicksort algorithm.