mixpplus
8/28/2019 - 12:36 PM

常见的五中排序算法

常见的五中排序算法

package com.ingin.bullsort.jiecheng;

import java.util.Arrays;

public class SortDemo {
    public static void main(String[] args) {
        int[] arr = {1, 6, 2, 8, 9, 2};
        bubbleSort(arr);
        System.out.println(Arrays.toString(arr));
        System.out.println("-----------------------");
        int[] arr1 = {1, 6, 2, 8, 9, 2};
        quickSort(arr1, 0, arr.length - 1);
        System.out.println(Arrays.toString(arr1));
        System.out.println("----------------------");
        int[] arr2 = {1, 6, 2, 8, 9, 2};
        selectSort(arr2);
        System.out.println(Arrays.toString(arr2));
        System.out.println("---------------------");
        int[] arr3 = {1, 6, 2, 8, 9, 2};
        insertSort(arr3);
        System.out.println(Arrays.toString(arr3));
        System.out.println("---------------------------");
        int[] arr4 = {1, 6, 2, 8, 9, 2};
        shellSort(arr4);
        System.out.println(Arrays.toString(arr4));


    }

    public static void bubbleSort(int[] arr) {
        for (int i = 0; i < arr.length - 1; i++) {
            boolean isSorted = true;
            for (int j = 0; j < arr.length - 1 - i; j++) {
                if (arr[j] > arr[j + 1]) {
                    isSorted = false;
                    int temp = arr[j];
                    arr[j] = arr[j + 1];
                    arr[j + 1] = temp;
                }
            }
            if (isSorted) {
                return;
            }
        }
    }

    public static void quickSort(int[] arr, int low, int high) {
        if (low >= high) {
            return;
        }

        int left = low;
        int right = high;
        int key = arr[left];
        while (left < right && arr[right] >= key) {
            right--;
        }
        arr[left] = arr[right];
        while (left < right && arr[left] <= key) {
            left++;
        }
        arr[right] = arr[left];
        arr[left] = key;
        quickSort(arr, low, left - 1);
        quickSort(arr, left + 1, high);
    }

    public static void selectSort(int[] arr) {
        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;
                }
            }
            int temp = arr[min];
            arr[min] = arr[i];
            arr[i] = temp;
        }
    }

    public static void insertSort(int[] arr) {
        for (int i = 1; i < arr.length; i++) {
            int current = arr[i];
            int position = i;
            while (position > 0 && arr[position - 1] > current) {
                arr[position] = arr[position - 1];
                position--;
            }
            arr[position] = current;
        }
    }

    public static void shellSort(int[] arr) {
        int step = arr.length / 2;
        while (step > 0) {
            for (int i = step; i < arr.length; i++) {
                while (i >= step && arr[i-step] > arr[i]){
                    int temp = arr[i-step];
                    arr[i-step] = arr[i];
                    arr[i] = temp;
                    i -= step;
                }
            }
            step /= 2;
        }
    }
}