Bubble Sort

向大端冒泡排序

public class Bubble {
    /**
     * 向大端冒泡排序
     *
     * @param arr
     * @param <T>
     */
    public static <T extends Comparable<? super T>> void bubbleSort(T[] arr) {
        for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j < arr.length - i - 1; j++) {
                if (arr[j].compareTo(arr[j + 1]) > 0) {
                    swap(arr, j, j + 1);
                }
            }
        }
    }

    public static void swap(Object[] arr, int i, int j) {
        Object temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }

    public static <T extends Comparable<? super T>> void printArray(T[] arr) {
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
        System.out.println();
    }

    public static void main(String[] args) {
        Integer[] arr = {1, 5, 9, 7, 3, 10, 2, 8, 6, 4};
        bubbleSort(arr);
        printArray(arr);
    }
}

　　

向小端冒泡排序

public class Bubble {
    /**
     * 向小端冒泡排序
     *
     * @param arr
     * @param <T>
     */
    public static <T extends Comparable<? super T>> void bubbleSort(T[] arr) {
        for (int i = 0; i < arr.length; i++) {
            for (int j = arr.length - 1; j > 0; j--) {
                if (arr[j].compareTo(arr[j - 1]) < 0) {
                    swap(arr, j - 1, j);
                }
            }
        }
    }

    public static void swap(Object[] arr, int i, int j) {
        Object temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }

    public static <T extends Comparable<? super T>> void printArray(T[] arr) {
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
        System.out.println();
    }

    public static void main(String[] args) {
        Integer[] arr = {1, 5, 9, 7, 3, 10, 2, 8, 6, 4};
        bubbleSort(arr);
        printArray(arr);
    }
}

　　

鸡尾酒排序

public class Bubble {
    /**
     * 鸡尾酒排序
     *
     * @param arr
     * @param <T>
     */
    public static <T extends Comparable<? super T>> void bubbleSort(T[] arr) {
        int low = 0;
        int high = arr.length - 1;
        while (low < high) {
            for (int i = low; i < high; i++) {
                if (arr[i].compareTo(arr[i + 1]) > 0) {
                    swap(arr, i, i + 1);
                }
            }
            high--;
            for (int j = high; j > low; j--) {
                if (arr[j].compareTo(arr[j - 1]) < 0) {
                    swap(arr, j - 1, j);
                }
            }
            low++;
        }
    }

    public static void swap(Object[] arr, int i, int j) {
        Object temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }

    public static <T extends Comparable<? super T>> void printArray(T[] arr) {
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
        System.out.println();
    }

    public static void main(String[] args) {
        Integer[] arr = {5, 1, 9, 7, 3, 10, 2, 8, 6, 4};
        bubbleSort(arr);
        printArray(arr);
    }
}　　

冒泡排序优化--标识符

public class Bubble {
    /**
     * 冒泡排序优化--标记符
     *
     * @param arr
     * @param <T>
     */
    public static <T extends Comparable<? super T>> void bubbleSort(T[] arr) {
        for (int i = 0; i < arr.length; i++) {
            boolean flag = true;
            for (int j = 0; j < arr.length - i - 1; j++) {
                if (arr[j].compareTo(arr[j + 1]) > 0) {
                    swap(arr, j, j + 1);
                    flag = false; //这层循环有交换
                }
            }
            if (flag) {//可以退出循环了,已有序
                break;
            }
        }
    }

    public static void swap(Object[] arr, int i, int j) {
        Object temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }

    public static <T extends Comparable<? super T>> void printArray(T[] arr) {
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
        System.out.println();
    }

    public static void main(String[] args) {
        Integer[] arr = {5, 1, 9, 7, 3, 10, 2, 8, 6, 4};
        bubbleSort(arr);
        printArray(arr);
    }
}

冒泡排序优化--标记位

public class Bubble {
    /**
     * 冒泡排序优化--标记符
     *
     * @param arr
     * @param <T>
     */
    public static <T extends Comparable<? super T>> void bubbleSort(T[] arr) {
        for (int i = 0, pos = 0; i < arr.length; i = arr.length - pos) {
            pos = 0;
            for (int j = 0; j < arr.length - i - 1; j++) {
                if (arr[j].compareTo(arr[j + 1]) > 0) {
                    swap(arr, j, j + 1);
                    pos = j + 1;//说明pos后面的元素都已有序,不需要进行比较了
                }
            }
        }
    }

    public static void swap(Object[] arr, int i, int j) {
        Object temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }

    public static <T extends Comparable<? super T>> void printArray(T[] arr) {
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
        System.out.println();
    }

    public static void main(String[] args) {
        Integer[] arr = {5, 1, 9, 7, 3, 10, 2, 8, 6, 4};
        bubbleSort(arr);
        printArray(arr);
    }
}