冒泡排序

源码实现

package csdn.dreamzuora.sort;import java.util.List;/*** Title: 冒泡排序* Description:* 冒泡排序思想是把相邻的元素进行两两比较，当前面元素大于后面元素则进行交换* @version 1.0* @author: weijie* @date: 2020/10/22 17:50*/
public class BubbleSort extends Sort<Integer>{@Overridepublic void sort(List<Integer> array) {if (array == null || array.isEmpty()){return;}int size = array.size();for (int i = 0; i < size - 1; i++){for (int j = 0; j < size - 1; j++){if (array.get(j) > array.get(j + 1)){int temp = array.get(j + 1);array.set(j + 1, array.get(j));array.set(j, temp);}}}}
}

单元测试

package csdn.dreamzuora.sort;import com.sun.deploy.util.StringUtils;
import org.junit.Test;
import org.junit.jupiter.api.Assertions;import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;import static org.junit.Assert.*;/*** Title:* Description:** @version 1.0* @author: weijie* @date: 2020/10/22 18:33*/
public class BubbleSortTest {BubbleSort bubbleSort = new BubbleSort();@Testpublic void sort() {List<Integer> sortList = Arrays.asList(3, 5, 4, 0, 1);List<Integer> expectList = Arrays.asList(0, 1, 3, 4, 5);bubbleSort.sort(sortList);Assertions.assertEquals(expectList, sortList);}
}

优化

package csdn.dreamzuora.sort;import java.util.List;/*** Title: 冒泡排序优化* Description:* 优化：在外层循环处，设置标志isSort，默认为排好，如果不交换则跳出本次循环* @version 1.0* @author: weijie* @date: 2020/10/22 18:50*/
public class BubbleSortPlus extends Sort<Integer>{@Overridepublic void sort(List<Integer> array) {if (array == null || array.isEmpty()){return;}int size = array.size();for (int i = 0; i < size - 1; i++){boolean isSort = true;for (int j = 0; j < size - 1; j++){if (array.get(j) > array.get(j + 1)){isSort = false;int temp = array.get(j + 1);array.set(j + 1, array.get(j));array.set(j, temp);}}if (isSort){break;}}}
}

快速排序

源码实现

package csdn.dreamzuora.sort;import java.util.List;/*** Title: 快速排序* Description:* 快速排序每一轮找出一个标准值，大于该值的放在右边，小于该值放在左边，从而把数组拆分成两部分，这种思路叫做分治法** @version 1.0* @author: weijie* @date: 2020/10/22 17:50*/
public class QuickSort extends Sort<Integer> {/**** @param a 数组* @param left 头指针* @param right 尾指针*/@Overridepublic void sort(List<Integer> a, int left, int right) {if (left >= right){return;}int value = a.get(left);//用来控制分治头指针、尾指针int i = left;int j = right;while (left < right){//先移动尾指针while (right != left && a.get(right) >= value){right --;}//再移动头指针while (left != right && a.get(left) <= value){left ++;}//如果指针重合，则确定了value下标，进行交换if (left == right){a.set(i, a.get(left));a.set(left, value);//分治sort(a, i, left - 1);sort(a, left + 1, j);}//如果指针没有重合则进行交换头尾指针值else {int temp = a.get(left);a.set(left, a.get(right));a.set(right, temp);}}}/*** 单边循环法:以后再研究* @param array*/public void sort2(List<Integer> array){}
}

单元测试

package csdn.dreamzuora.sort;import org.junit.Test;import java.util.Arrays;
import java.util.List;import static org.junit.Assert.*;/*** Title:* Description:** @version 1.0* @author: weijie* @date: 2020/10/23 18:18*/
public class QuickSortTest {QuickSort quickSort = new QuickSort();@Testpublic void sort() {List<Integer> list = Arrays.asList(5, 8, 6, 3, 9, 2, 1, 7);quickSort.sort(list, 0, list.size() - 1);System.out.println(list);}
}