[Java]排序算法

package org.example;

import org.junit.jupiter.api.Test;

import java.util.Arrays;

public class Sort {

    @Test
    public void testBubblingSort() {
        int[] arr = {4, 5, 1, 44, 2, 5, 7};
        bubblingSort(arr);
        System.out.println(Arrays.toString(arr));
    }

    
    public void bubblingSort(int[] arr) {
        for (int i = 0; i < arr.length - 1; i++) {
            for (int j = 0; j < arr.length - i - 1; j++) {
                if (arr[j] > arr[j + 1]) {
                    int temp = arr[j];
                    arr[j] = arr[j + 1];
                    arr[j + 1] = temp;
                }
            }
        }
    }
    
}

输出

[1, 2, 4, 5, 5, 7, 44]

package org.example;

import org.junit.jupiter.api.Test;

import java.util.Arrays;

public class Sort {

    @Test
    public void testQuickSort() {
        int[] arr = {4, 5, 1, 44, 2, 5, 7};
        quickSort(arr, 0, arr.length - 1);
        System.out.println(Arrays.toString(arr));
    }

    
    public void quickSort(int[] arr, int start, int end) {
        if (start >= end) {
            return;
        }
        int base = arr[start];
        int i = start;
        int j = end;
        boolean fromTail = true;
        while (i < j) {
            if (fromTail) {
                if (arr[j] < base) {
                    arr[i] = arr[j];
                    i++;
                    fromTail = false;
                } else {
                    j--;
                    fromTail = true;
                }
            } else {
                if (arr[i] > base) {
                    arr[j] = arr[i];
                    j--;
                    fromTail = true;
                } else {
                    i++;
                    fromTail = false;
                }
            }
            if (i == j) {
                arr[i] = base;
                break;
            }
        }
        quickSort(arr, start, i - 1);
        quickSort(arr, i + 1, end);
    }
    
}

输出

[1, 2, 4, 5, 5, 7, 44]