快排、冒泡、选择排序

小灰灰 2024-03-27 14:46 79阅读 0赞

## 一：快速排序 \*\*\*\*\*\* ##

public class Qsort {
    
        public static void main(String[] args) {
            int[] a = new int[] { 10, 2, 6, 3, 9, 0 };
            int b = a.length;
            Qsort(a, 0, b - 1);
    // 输出数组
            System.out.println("从大到小排序：");
            for (int i = 0; i < b; i++) {
                System.out.print(a[i] + " ");
            }
            System.out.println();
    // 输出数组
            System.out.println("从小到大排序：");
            for (int i = b - 1; i >= 0; i--) {
                System.out.print(a[i] + " ");
            }
            System.out.println();
            System.out.println("最小值：" + a[0]);
            System.out.println("最大值：" + a[5]);
            
        }
    // L表示数组最小下标，R表示数组最大下标
        public static void Qsort(int a[], int L, int R) {
            if (L < R) {
                int pivot = part(a, L, R);
                Qsort(a, L, pivot - 1);
                Qsort(a, pivot + 1, R);
            }
        }
    // 划分数组
        public static int part(int a[], int L, int R) {
            int pivot = a[L];
            while (L < R) {
                while (L < R && a[R] >= pivot) {
                    R--;
                }
                a[L] = a[R];
                while (L < R && a[L] <= pivot) {
                    L++;
                }
                a[R] = a[L];
            }
            a[L] = pivot;
            return L;
        }
        
    }

int\[\] a = new int\[\] \{ 10, 2, 6, 3, 9, 0 \};

![c4092c4c1b4ed338bcda62629ab691d5.png][]

## 二：冒泡排序 ##

public class Bubble {
    
        public static void main(String[] args) {
            System.out.println("------冒泡-------");
            bubble();  //  将数组地址传递给方法
        }
        
        public static void bubble() {
            int[] arr = { 3, 22, 5, 1, 4 };
            int a;
            for (int i = 0; i < arr.length - 1; i++) {
                for (int j = 0; j < arr.length - 1 - i; j++) {
                    if (arr[j] > arr[j + 1]) {
                        a = arr[j];
                        arr[j] = arr[j + 1];
                        arr[j + 1] = a;
                    }
                }
    //  输出中间的过程
                System.out.print("第" + i + "趟：" );
                for (int k = 0; k < arr.length; k++) {
                    System.out.print(arr[k] + " ");
                }
                System.out.println();
    
            }
            for (int i = 0; i < arr.length; i++) {
                System.out.print(arr[i] + " ");
            }
            System.out.println("\n----------");
        }
    
    }

![b9f9e50a61f15aa7941cf632193435c6.png][]

## 三：选择排序 ##

public static void main(String[] args) {
            System.out.println("------选排-------");
            selection();   // 将数组地址传递给方法
        }
    
        public static void selection() {
            int[] arr = { 5, 4, 3, 2, 1 };
            for (int i = 0; i < arr.length - 1; i++) {
                int min = i;
                for (int j = i + 1; j < arr.length; j++) {
                    if (arr[min] > arr[j]) {
                        min = j;
                    }
                }
                if (min != i){
                    int temp = arr[i];
                    arr[i] = arr[min];
                    arr[min] = temp;
                }
    //  输出中间的过程
                System.out.print("第" + (i + 1) + "趟：");
                for (int k = 0; k < arr.length; k++) {
                    System.out.print(arr[k] + " ");
                }
                System.out.println();
            }
    
            for (int i = 0; i < arr.length; i++) {
                System.out.print(arr[i] + " ");
            }
    
        }
    
    }

int\[\] arr = \{ 5, 4, 3, 2, 1 \};

![01ba197344dd92de657c2dc81d281111.png][]

int\[\] arr = new int\[\]\{5, 4, 3, 2, 1\};

Sort(arr); // 将**数组地址**传递给方法

PS:每一趟要看数组排序成功，可以使用Arrays.toString();

该方法返回为字符串型。

int[] a = new int[]{1,23,42,3,2,1,1};
            System.out.println(Arrays.toString(a));
            
            String str = Arrays.toString(a);
            System.out.println("2:" + str);

![c0f6f9679fbe8b9682abded75eaa096c.png][]

[c4092c4c1b4ed338bcda62629ab691d5.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/27/1a55f79cafe54939a8905c3b80430d26.png
[b9f9e50a61f15aa7941cf632193435c6.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/27/782a2013b05c4d77b33e97dbfbd51d3c.png
[01ba197344dd92de657c2dc81d281111.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/27/76467dc542c04515a0f5d22d0b7300fd.png
[c0f6f9679fbe8b9682abded75eaa096c.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/27/08a45dbcc2944b39899b359400dca2ed.png