排序算法实现 C/C++

笔试面试，经常让写排序算法，十一假期没敲代码，手都生了，今天正好回忆下，重新写了几个简单的排序算法：选择排序、冒泡排序、插入排序、堆排序、快排、非递归快排、归并排序。与大家分享下，上代码：

#include <iostream>using namespace std;struct node{int low;int high;};

/*选择排序*/void selectsort(int arr[],int n){int i, j, min;for (i = 0; i < n; i++){min = i;for( j = i+1; j < n; j++ ){if( arr[j] < arr[min] )min = j;}if( min != i )swap(arr[i], arr[min]);}}
/*冒泡排序*/
void bubblesort(int arr[], int n){int flag = 0;while (flag != 1){for( int j = 0; j < n; j++ ){flag = 1;for (int i = n-1; i >= j; i--){if (arr[i-1] > arr[i]){flag = 0;swap(arr[i-1], arr[i]);}}}}}

/*插入排序*/
void insertsort(int arr[], int n){int flag = 0;int temp;for(int i = 1; i < n; i++){temp = arr[i];for (int j = i-1; j >= 0; j--){flag = 1;if(arr[j] > temp){flag = 0;swap(arr[j], arr[j+1]);}if(flag == 1)break;}}}

/*堆排序*/
void sift(int arr[], int n, int index){int i;while(index * 2 + 1 < n){i = index * 2 + 1;if(i < n-1 && arr[i] < arr[i+1])i = i + 1;if(arr[i] > arr[index]){swap(arr[i],arr[index]);index = i;}else break;}}void heapsort(int arr[],int n){for(int i = n / 2 - 1; i >= 0;i--){sift(arr, n, i);}for(int i = n - 1; i > 0; i--){swap(arr[i], arr[0]);sift(arr, i, 0);}}

/*快速排序*/
void quicksort(int arr[],int begin, int end){int i = begin;int j = end;while(i < j){while( j > i && arr[j] > arr[i])j--;if(i < j){swap(arr[i++],arr[j]);}while(j > i && arr[i] < arr[j])i++;if(i < j){swap(arr[i], arr[j--]);}}if(begin < i-1)quicksort(arr, begin, i-1);if(i+1 < end)quicksort(arr, i+1, end);}

/*非递归快排*/
void quicksort_stack(int arr[], int begin, int end){int i;int j;struct node s[100];int top = 0;s[top].low = begin;s[top].high = end;while(top >= 0){i = s[top].low;j = s[top].high;top--;begin = i;end = j;while( i < j){while(i < j && arr[j] > arr[i])j--;if(i < j)swap(arr[i++],arr[j]);while(i < j && arr[i] < arr[j])i++;if (i < j)swap(arr[i],arr[j--]);}if(begin < i-1){top++;s[top].low = begin;s[top].high = i-1;}if(i+1 < end){top++;s[top].low = i+1;s[top].high = end;}}}

/*归并排序*/
void merge(int arr[], int p, int q, int r){int temp[100]={0};//辅助数组int end1 = q;int begin1 = p;q = q + 1;int i = 0;while(p <= end1 && q <= r){if(arr[p] <= arr[q])temp[i++] = arr[p++];elsetemp[i++] = arr[q++];}if(p > end1){while(q <= r)temp[i++] = arr[q++]; }else{while( p <= end1)temp[i++] = arr[p++];}i = 0;for(int j = begin1; j <= r; j++){arr[j] = temp[i++];}}void mergesort(int arr[], int p, int r){int q;if(p < r){q = (int)((p+r)/2);mergesort(arr, p, q);mergesort(arr, q+1, r);merge(arr, p, q, r);}}int main(){int i;int arr[] = {13, 15, 6, 10, 20, 8, 3, 19};int n = sizeof(arr) / sizeof(arr[0]);//selectsort(arr, n);//选择排序//bubblesort(arr, n);//冒泡排序//insertsort(arr, n);//插入排序//heapsort(arr, n);//堆排序//quicksort(arr, 0, n-1);        //快排//quicksort_stack(arr, 0, n-1);                //快排非递归mergesort(arr, 0, n-1);        //归并排序for (i = 0;i < n; i++){cout << arr[i] << ",";}cout << endl;return 0;}