public class CocktailSort {
    
    /**
     * 鸡尾酒排序
     */
    public static void sort(int[] arr) {
        int left = 0;
        int right = arr.length - 1;
        boolean swapped = true;
        
        while (left < right && swapped) {
            swapped = false;
            
            // 从左到右冒泡，将最大元素移到 right 位置
            for (int i = left; i < right; i++) {
                if (arr[i] > arr[i + 1]) {
                    swap(arr, i, i + 1);
                    swapped = true;
                }
            }
            right--;
            
            if (!swapped) break;
            
            swapped = false;
            // 从右到左冒泡，将最小元素移到 left 位置
            for (int i = right; i > left; i--) {
                if (arr[i] < arr[i - 1]) {
                    swap(arr, i, i - 1);
                    swapped = true;
                }
            }
            left++;
        }
    }
    
    /**
     * 鸡尾酒排序（优化版本，记录最后一次交换位置）
     */
    public static void sortOptimized(int[] arr) {
        int left = 0;
        int right = arr.length - 1;
        int lastSwapLeft = 0;
        int lastSwapRight = arr.length - 1;
        
        while (left < right) {
            // 从左到右
            int newRight = left;
            for (int i = left; i < right; i++) {
                if (arr[i] > arr[i + 1]) {
                    swap(arr, i, i + 1);
                    newRight = i;
                }
            }
            right = newRight;
            if (left >= right) break;
            
            // 从右到左
            int newLeft = right;
            for (int i = right; i > left; i--) {
                if (arr[i] < arr[i - 1]) {
                    swap(arr, i, i - 1);
                    newLeft = i;
                }
            }
            left = newLeft;
        }
    }
    
    /**
     * 鸡尾酒排序（泛型版本）
     */
    public static <T extends Comparable<T>> void sortGeneric(T[] arr) {
        int left = 0;
        int right = arr.length - 1;
        boolean swapped = true;
        
        while (left < right && swapped) {
            swapped = false;
            for (int i = left; i < right; i++) {
                if (arr[i].compareTo(arr[i + 1]) > 0) {
                    T temp = arr[i];
                    arr[i] = arr[i + 1];
                    arr[i + 1] = temp;
                    swapped = true;
                }
            }
            right--;
            
            if (!swapped) break;
            
            swapped = false;
            for (int i = right; i > left; i--) {
                if (arr[i].compareTo(arr[i - 1]) < 0) {
                    T temp = arr[i];
                    arr[i] = arr[i - 1];
                    arr[i - 1] = temp;
                    swapped = true;
                }
            }
            left++;
        }
    }
    
    private static void swap(int[] arr, int i, int j) {
        int temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }
}