二分查找算法与快速排序

public class BinarySearch {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
        int[] array = {5,13,19,21,37,56,64,75,80,88,92};
		System.out.println(BinarySearch.bindarySearch3(array, 0,array.length-1,80));
		int i = Arrays.binarySearch(array, 80);
		System.out.println(i);
	}
	/**
	 * @param array[] 有序整型数组
	 * @param searchkey 要查找的值
	 * @return 返回searchkey 在array[]中的位置
	 */
	static int  bindarySearch(int array[],int searchkey){
		int low = 0;
		int high = array.length - 1;
		while(low <= high){
			int middle = (low + high)/2;
			if(array[middle] == searchkey){
				return middle;
			}else if(array[middle] > searchkey){
				high = middle -1;
			}else if(array[middle] < searchkey){
				low = middle + 1;
			}
		}
		return -1;
	}//以下是递归实现的，注意边界值。
	static int bindarySearch3(int array[],int low,int high,int searchkey){
		if(low > high){
			return -1;
		}
		int middle = (low + high)/2;
		if(array[middle] == searchkey){
			return middle;
		}else if(array[middle] > searchkey){
			high = middle - 1;
			return bindarySearch3(array,low,high,searchkey);
		}else if(array[middle] < searchkey){
			low = middle + 1 ;
			return bindarySearch3(array,low,high,searchkey);
		}
		return -1;
	}
}

public class QuickSort {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		int[] array = {49,38,65,97,76,13,27,51};
		System.out.println(partition(array,0,array.length-1));
		System.out.println(Arrays.toString(array));
		
		quickSort(array,0,array.length-1);
		System.out.println(Arrays.toString(array));

	}
	static void quickSort(int[] array,int left,int right){
		if(left < right){
			int i = partition(array,left,right);
			quickSort(array,left,i-1);
			quickSort(array,i+1,right);
			
		}
	}
	
	/**
	 * 
	 * @param array 
	 * @param left  
	 * @param right
	 * @return基准记录所在数组的位置
	 */
	static int  partition(int[] array,int left ,int right ){
		
		int base = array[left];//基准记录
		
		while(left != right){
			while(array[right] >= base && left<right){
				right--;
			}
			if(left<right){
				int temp = array[right];
				array[right] = array[left];
				array[left] = temp;
				left+=1;
			}
			while(array[left] <= base && left<right){
				left++;
			}
			if(left<right){
				int temp = array[left];
				array[left] = array[right];
				array[right] = temp;
				right-=1;
			}
		}
		return left;//or return right;
	}

}