算法与数据结构之排序算法

 选择排序

package com.zy.base.class001;

import java.util.Arrays;

public class Code01_SelectionSort {
    public static void selectionSort(int[] arr) {
        if (arr == null || arr.length < 2) {
            return;
        }

        for (int i = 0; i < arr.length - 1; i++) {
            // 最小值的位置在哪
            int minIndex = i;
            for (int j = i + 1; j < arr.length; j++) {
                minIndex = arr[j] < arr[minIndex] ? j : minIndex;
            }
            swap(arr, i, minIndex);
        }
    }

    private static void swap(int[] arr, int i, int minIndex) {
        int tmp = arr[i];
        arr[i] = arr[minIndex];
        arr[minIndex] = tmp;
    }

    public static void main(String[] args) {
        int[] arr = {6, 3, 1, 7, 10, 5, 11};
        selectionSort(arr);
        System.out.println(Arrays.toString(arr));
    }
}

冒泡排序：

package com.zy.base.class001;

import java.util.Arrays;

public class Code02_BubbleSort {
    public static void bubbleSort(int[] arr) {
        if (arr == null || arr.length < 2) {
            return;
        }
        for (int i = arr.length - 1; i > 0; i--) {
            for (int j = 0; j < i; j++) {
                if (arr[j] > arr[j + 1]) {
                    swap(arr, j, j + 1);
                }
            }
        }
    }

    private static void swap(int[] arr, int i, int minIndex) {
        int tmp = arr[i];
        arr[i] = arr[minIndex];
        arr[minIndex] = tmp;
    }

    public static void main(String[] args) {
        int[] arr = {6, 3, 1, 7, 10, 5, 11};
        bubbleSort(arr);
        System.out.println(Arrays.toString(arr));
    }
}