常见算法
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace Sort { public class Sort { ///<summary> /// 插入排序--稳定排序 ///</summary> ///<param name="list"></param> public static void InsertSort(List<int> list) { int j, tmp; for (int i =1; i < list.Count; i++) { j = i; tmp = list[i]; while (j >0&& tmp <= list[j -1]) { list[j] = list[j -1]; j--; } list[j] = tmp; } } ///<summary> /// 希尔排序 ///</summary> ///<param name="list"></param> public static void ShellSort(List<int> list) { int j, tmp; int h =3; while (h>0) { for (int i = h; i < list.Count; i++) { tmp = list[i]; j = i; while ((j > h -1) && tmp < list[j - h]) { list[j] = list[j - h]; j -= h; } list[j] = tmp; } h = (h -1) %3; } } ///<summary> /// 冒泡排序--稳定排序 ///</summary> ///<param name="list"></param> public static void BubbleSort(List<int> list) { if (list ==null|| list.Count <1) { return; } int tmp; for (int i =0; i < list.Count -1; ++i) { bool flag=false; for (int j = list.Count -1; j >i+1; j--) { if (list[j] > list[j +1]) { tmp = list[j]; list[j] = list[j +1]; list[j +1] = tmp; flag=true; } if(flag==false) { return; } } } } ///<summary> /// 选择排序--直接选择排序 ///</summary> ///<param name="list"></param> public static void SelectSort(List<int> list) { int min, tmp; for (int i =0; i < list.Count; i++) { min = i; for (int j = i +1; j < list.Count; j++) { if (list[j] < list[min]) { min = j; } } if (i != min) { tmp = list[i]; list[i] = list[min]; list[min] = tmp; } } } ///<summary> /// 堆排序 ///</summary> ///<param name="list"></param> public static void HeapSort(List<int> list) { int n = list.Count; for (int i = n/2-1; i >=0; i--) { Sift(list, i, n -1); } for (int i = n -1; i >=1; i--) { int tmp = list[0];//取堆顶元素 list[0] = list[i];//让堆中最后一个元素上移到堆顶位置 list[i] = tmp;//此时list[i]已不在堆中,用于存放排好序的元素 Sift(list, 0, i -1);//重新调整堆 } } private static void Sift(List<int> list, int low, int high)//建堆过程 { //i为欲调整子树的根结点的索引号,j为这个结点的左孩子 int i = low, j =2* i +1; int tmp = list[i];//记录双亲结点的值 while (j<=high) {//如果左孩子小于右孩子,则将欲交换的孩子结点指向右孩子 if (j < high && list[j] < list[j +1]) { j++;//j指向右孩子 } if (tmp < list[j])//如果双亲结点小于它的孩子结点 { list[i] = list[j];//交换双亲结点和它的孩子结点 i = j;//以交换后的孩子结点为根,继续调整它的子树 j =2* i +1;//j此时代表交换后的孩子结点的左孩子 } else//调整完毕 { break; } } list[i] = tmp;//使最初被调整的结点放入正确的位置 } ///<summary> /// 归并排序--稳定排序 ///</summary> ///<param name="list"></param> ///<param name="low"></param> ///<param name="high"></param> public static void MergeSort(List<int> list, int low, int high) { if (low < high) { int mid = (low + high) /2; MergeSort(list, low, mid); MergeSort(list, mid +1, high); Merge(list, low, mid, high); } } private static void Merge(List<int> list, int low, int mid, int high) {//listTmp为临时存放空间,存放合并后的数据 List<int> listTmp =new List<int>(high - low +1); int i = low, j = mid +1, k =0;//k为listTmp的下标 while (i <= mid && j <= high) { listTmp[k++] = (list[i] < list[j]) ? list[i++] : list[j++]; } while (i <= mid) { listTmp[k++] = list[i++]; } while (j <= high) { listTmp[k++] = list[j++]; } for (i = low, k=0; i <= high;i++,k++ ) { list[i] = listTmp[k]; } } ///<summary> /// 快速排序 ///</summary> ///<param name="list"></param> public static void QuickSort(List<int> list) { QuickSort(list, 0, list.Count -1); } public static void QuickSort(List<int> list, int low, int high) { if (low < high) { int i = low, j = high, tmp = list[i]; while (i < j) { while (i < j && list[j] >= tmp) { j--; } list[i] = list[j]; while (i < j && list[i] <= tmp) { i++; } list[j] = list[i]; } list[i] = tmp; QuickSort(list, low, i -1); QuickSort(list, i +1, high); } } } }