排序算法是计算机科学中常见的一类算法,用于将一组数据按照特定的顺序进行排列。下面介绍几种常见的排序算法:
#include <iostream>
#include <cstdlib>
#include <ctime>
// 冒泡排序 bubbleSort 两两比较
void bubbleSort(int arr[], int n) {
for (int i = 0; i < n-1; i++) {
for (int j = 0; j < n-i-1; j++) {
if (arr[j] > arr[j+1]) {
std::swap(arr[j], arr[j+1]);
}
}
}
}
// 选择排序 selectionSort 选最小值
void selectionSort(int arr[], int n) {
for (int i = 0; i < n-1; i++) {
int minIndex = i;
for (int j = i+1; j < n; j++) {
if (arr[j] < arr[minIndex]) {
minIndex = j;
}
}
std::swap(arr[i], arr[minIndex]);
}
}
// 插入排序 insertionSort 依次成序
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;
}
}
// 归并排序 mergeSort
void merge(int arr[], int left, int mid, int right) {
int n1 = mid - left + 1;
int n2 = right - mid;
int* L = new int[n1];
int* R = new int[n2];
for (int i = 0; i < n1; i++) {
L[i] = arr[left + i];
}
for (int j = 0; j < n2; j++) {
R[j] = arr[mid + 1 + j];
}
int i = 0;
int j = 0;
int k = left;
while (i < n1 && j < n2) {
if (L[i] <= R[j]) {
arr[k] = L[i];
i++;
} else {
arr[k] = R[j];
j++;
}
k++;
}
while (i < n1) {
arr[k] = L[i];
i++;
k++;
}
while (j < n2) {
arr[k] = R[j];
j++;
k++;
}
delete[] L;
delete[] R;
}
void mergeSort(int arr[], int left, int right) {
if (left < right) {
int mid = left + (right - left) / 2;
mergeSort(arr, left, mid);
mergeSort(arr, mid + 1, right);
merge(arr, left, mid, right);
}
}
// 快速排序 quickSort
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++;
std::swap(arr[i], arr[j]);
}
}
std::swap(arr[i+1], arr[high]);
return i+1;
}
void quickSort(int arr[], int low, int high) {
if (low < high) {
int pi = partition(arr, low, high);
quickSort(arr, low, pi - 1);
quickSort(arr, pi + 1, high);
}
}
// 打印数组
void printArray(int arr[], int size) {
for (int i = 0; i < size; i++) {
std::cout << arr[i] << " ";
}
std::cout << std::endl;
}
int main() {
const int SIZE = 10;
// 生成随机整数数组
int arr[SIZE];
srand(time(0));
for (int i = 0; i < SIZE; i++) {
arr[i] = rand() % 100; // 生成 0 到 99 的随机数
}
std::cout << "Original array: ";
printArray(arr, SIZE);
// 使用冒泡排序进行排序
bubbleSort(arr, SIZE);
std::cout << "Array after bubble sort: ";
printArray(arr, SIZE);
// 使用选择排序进行排序
selectionSort(arr, SIZE);
std::cout << "Array after selection sort: ";
printArray(arr, SIZE);
// 使用插入排序进行排序
insertionSort(arr, SIZE);
std::cout << "Array after insertion sort: ";
printArray(arr, SIZE);
// 使用归并排序进行排序
mergeSort(arr, 0, SIZE-1);
std::cout << "Array after merge sort: ";
printArray(arr, SIZE);
// 使用快速排序进行排序
quickSort(arr, 0, SIZE-1);
std::cout << "Array after quick sort: ";
printArray(arr, SIZE);
return 0;
}
编译运行:
g++ -o main main.cpp && ./main