一、算法介绍

二、代码实现

/**
 *	二分查找，递归与非递归形式
 */
public class BinarySearch {

	public int searchValue(int [] data, int indexValue) {
		int start = 0;
		int middle = 0;
		int end = data.length - 1;
		
		while (start <= end) {
			middle = (start + end)/2;
			
			if (data[middle] < indexValue) {
				start = middle + 1;
			} else if (data[middle] > indexValue) {
				end = middle - 1;
			} else {
				return middle;
			}
			
			
		}	
		return -1;
	}
	
	
	public int searchValue(int [] data, int start, int end, int indexValue) {
		if (start > end) {
			return -1;
		}
		
		int middle = (start + end)/2;
		if (data[middle] < indexValue) {
			return searchValue(data, middle+1, end, indexValue);
		} else if (data[middle] > indexValue) {
			return searchValue(data, start, middle-1, indexValue);
		} else {
			return middle;
		}
	}
	
	
	public static void main(String[] args) {
		int[] arr = {2, 3, 5, 6, 8, 9};
		BinarySearch search = new BinarySearch();
		
		System.out.println(search.searchValue(arr, 9) == 5);
		System.out.println(search.searchValue(arr, 8) == 4);
		System.out.println(search.searchValue(arr, 6) == 3);
		System.out.println(search.searchValue(arr, 5) == 2);
		System.out.println(search.searchValue(arr, 3) == 1);
		System.out.println(search.searchValue(arr, 2) == 0);
		System.out.println(search.searchValue(arr, 10) == -1);
		
		
		System.out.println(search.searchValue(arr, 0, arr.length-1, 9) == 5);
		System.out.println(search.searchValue(arr, 0, arr.length-1, 8) == 4);
		System.out.println(search.searchValue(arr, 0, arr.length-1, 6) == 3);
		System.out.println(search.searchValue(arr, 0, arr.length-1, 5) == 2);
		System.out.println(search.searchValue(arr, 0, arr.length-1, 3) == 1);
		System.out.println(search.searchValue(arr, 0, arr.length-1, 2) == 0);
		System.out.println(search.searchValue(arr, 0, arr.length-1, 10) == -1);
	}
	
}

三、逐步演示

四、时间空间复杂度

五、参考资料：