java--数据结构--8种排序算法

1.直接插入排序

直接插入排序：public class SortArray {  public static void main(String[] args) {    int a[] = {2,4,6,1,3,8,9,7,5};    insertionSort(a);    for(int i = 0;i < a.length;i++)      System.out.print(a[i] + " ");  }// insertionSort必须为static方法，因为不能再静态上下文中引用非静态的方法  public static int[] insertionSort(int a[]) {    for(int i = 1;i < a.length;i++) {      for(int j = i;j > 0;j--) {        if(a[j] < a[j-1]) {          int temp = a[j];          a[j] = a[j-1];          a[j-1] = temp;        }      }    }    return a;  }}

2.折半插入排序

折半插入排序：public class SortArray {  public static void main(String[] args) {    int a[] = {2,4,6,1,3,8,9,7,5};    binaryInsertSort(a);    for(int i = 0;i< a.length;i++){      System.out.println(a[i] + "");    }  }  public static int[] binaryInsertSort(int a[]) {    for(int i = 1;i < a.length;i++) {      int temp = a[i];      int low = 0;      int high = i-1;      while(low <= high) {        int mid = (low + high)/2;       if(temp < a[mid]) {         high = mid - 1;       }else{         low = mid + 1;       }      }      for(int j = i; j >=low + 1;j--){        a[j] = a[j-1];      }      a[low] = temp;    }    return a;  }}

3.希尔排序

希尔排序public class SortArray {  public static void main(String[] args) {    int a[] = {2,4,6,1,3,8,9,7,5};    shellInsertSort(a);    for(int i = 0;i< a.length;i++){      System.out.println(a[i] + "");    }  }  public static int[] shellInsertSort(int a[]) {    int d = a.length;    while(true)    {      d = d/2;      for(int x = 0;x < d;x++){        for(int i = x + d;i < a.length;i = i + d) {          int temp = a[i];          int j;          // 注意判断条件j >= 0要在a[j] > temp前边，否则若j为负，a[j] > temp中数组不合法会运行报错          for(j = i - d; j >= 0 && a[j] > temp;j = j-d) {            a[j+d] = a[j];          }          a[j+d] = temp;        }      }      if(d == 1){        break;      }    }    return a;  }}

4.简单选择排序

简单选择排序public class SortArray {  public static void main(String[] args) {    int a[] = {2,4,6,1,3,8,9,7,5};    selectSort(a);    for(int i = 0;i< a.length;i++){      System.out.println(a[i] + "");    }  }  public static int[] selectSort(int a[]) {    int i,j,minIndex;    for(i = 0;i < a.length;i++){      minIndex = i;      for(j = i + 1;j < a.length;j++){        if(a[minIndex] > a[j]){          minIndex = j;        }      }      int temp = a[i];      a[i] = a[minIndex];      a[minIndex] = temp;    }    return a;  }}

5.堆排序

堆排序：（答案还有问题）public class SortArray {  public static void main(String[] args) {    int a[] = {2,4,6,1,3,8,9,7,5};    heapSort(a);    for(int i = 0;i< a.length;i++){      System.out.print(a[i] + " ");    }  }  public static int[] heapSort(int a[]) {    for(int i = a.length/2 - 1;i >= 0;--i){      heapAdjust(a,i);    }    for(int i = a.length - 1;i > 0;--i) {      int temp = a[i];      a[i] = a[0];      a[0] = temp;      heapAdjust(a,i);    }    return a;  }  public static int[] heapAdjust(int a[],int i) {    int temp = a[i];    int child = 2*i + 1;    while(child < a.length){      if(child + 1 < a.length && a[child] < a[child+1]) {        ++child;      }      if(a[i] < a[child]) {        a[i] = a[child];        i = child;        child = 2 * i + 1;      }else {        break;      }    }    a[i] = temp;    return a;  }}public class HeapSortTest {   public static void main(String[] args) {     int[] data5 = new int[] { 5, 3, 6, 2, 1, 9, 4, 8, 7 };       print(data5);      heapSort(data5);       System.out.println("排序后的数组：");     print(data5);   }   public static void swap(int[] data, int i, int j) {       if (i == j) {          return;       }       data[i] = data[i] + data[j];        data[j] = data[i] - data[j];        data[i] = data[i] - data[j];   }    public static void heapSort(int[] data) {        for (int i = 0; i < data.length; i++) {            createMaxdHeap(data, data.length - 1 - i);            swap(data, 0, data.length - 1 - i);            print(data);        }    }    public static void createMaxdHeap(int[] data, int lastIndex) {       for (int i = (lastIndex - 1) / 2; i >= 0; i--) {            // 保存当前正在判断的节点            int k = i;            // 若当前节点的子节点存在            while (2 * k + 1 <= lastIndex) {                // biggerIndex总是记录较大节点的值,先赋值为当前判断节点的左子节点               int biggerIndex = 2 * k + 1;                if (biggerIndex < lastIndex) {                   // 若右子节点存在，否则此时biggerIndex应该等于 lastIndex                   if (data[biggerIndex] < data[biggerIndex + 1]) {                        // 若右子节点值比左子节点值大，则biggerIndex记录的是右子节点的值                        biggerIndex++;                   }              }                if (data[k] < data[biggerIndex]) {                    // 若当前节点值比子节点最大值小，则交换2者得值，交换后将biggerIndex值赋值给k                   swap(data, k, biggerIndex);                   k = biggerIndex;                } else {                    break;                }            }        }   }    public static void print(int[] data) {       for (int i = 0; i < data.length; i++) {            System.out.print(data[i] + "\t");       }        System.out.println();    }}

6.冒泡排序

冒泡排序：public class SortArray {  public static void main(String[] args) {    int a[] = {2,4,6,1,3,8,9,7,5};    bubbleSort(a);    for(int i = 0;i< a.length;i++){      System.out.print(a[i] + " ");    }  }  public static int[] bubbleSort(int a[]) {    int i = a.length;    int temp,j;    while(i > 0) {      for(j = 0;j < i-1;j++) {        if(a[j] > a[j+1]) {          temp = a[j];          a[j] = a[j+1];          a[j+1] = temp;        }      }      i--;    }    return a;  }}

7.快速排序

快速排序：public class SortArray {  public static void main(String[] args) {    int a[] = {2,4,6,1,3,8,9,7,5};    quickSort(a,0,a.length-1);    for(int i = 0;i< a.length;i++){      System.out.print(a[i] + " ");    }  }  public static int[] quickSort(int a[],int left,int right) {    int dp;    if(left < right) {      dp = partition(a,left,right);      quickSort(a,left,dp - 1);      quickSort(a,dp + 1,right);    }    return a;  }  public static int partition(int a[], int left,int right) {    int temp;    int pivot = a[left];    while(left < right) {      while(left < right && a[right] > pivot) {        right--;      }      if(left < right) {        temp = a[left];        a[left] = a[right];        a[right] = temp;      }      while(left < right && a[left] < pivot) {        left++;      }      if(left < right) {        temp = a[left];        a[left] = a[right];        a[right] = temp;      }      a[left] = pivot;    }    return left;  }}

8.归并排序

归并排序：public class SortArray {  public static void main(String[] args) {    int a[] = {2,4,6,1,3,8,9,7,5};    mergeSort(a,0,a.length-1);    for(int i = 0;i < a.length;i++){      System.out.print(a[i] + " ");    }  }  public static int[] mergeSort(int a[],int low,int high) {    int mid = (low + high)/2;    if(low < high) {      mergeSort(a,low,mid);      mergeSort(a,mid+1,high);      merge(a,low,mid,high);    }    return a;  }  public static void merge(int a[],int low,int mid,int high) {    int array[] = new int[high - low +1];    //左指针    int i = low;    // 右指针    int j = mid + 1;    int k = 0;    // 把较小的数先移到新数组中    while(i <= mid && j <= high) {      if(a[i] < a[j]) {        array[k++] = a[i++];      }else {        array[k++] = a[j++];      }    }    // 把左边剩余的数移到数组    while(i <= mid) {      array[k++] = a[i++];    }    // 把右边剩余的数移到数组    while(j <= high) {      array[k++] = a[j++];    }    // 把新数组中的数覆盖a数组    for(int k2 = 0;k2 <array.length;k2++) {      a[k2 + low] = array[k2];    }  }}