二分查找java代码

package csdn.dreamzuora.query;/*** Title: 二分查找* Description:* 时间复杂度：log2N* @version 1.0* @author: weijie* @date: 2020/10/16 13:52*/
public class BinarySearch implements Search {int[] array;public BinarySearch(int[] array) {this.array = array;}@Overridepublic int search(int data) {int startIndex = 0;int endIndex = array.length - 1;int midIndex = startIndex + (endIndex - startIndex) / 2;while (midIndex >= startIndex && midIndex <= endIndex){if (array[midIndex] == data){return midIndex;}if (data > array[midIndex]){startIndex = midIndex + 1;}else {endIndex = midIndex - 1;}midIndex = startIndex + (endIndex - startIndex) / 2;}return -1;}
}

单元测试

package csdn.dreamzuora.query;import org.junit.Test;
import org.junit.jupiter.api.Assertions;import static org.junit.Assert.*;/*** Title:* Description:** @version 1.0* @author: weijie* @date: 2020/10/16 14:00*/
public class BinarySearchTest {@Testpublic void search() {int[] array = new int[10];for (int i = 0; i < 10; i++){array[i] = i;}BinarySearch binarySearch = new BinarySearch(array);Assertions.assertEquals(3, binarySearch.search(3));Assertions.assertEquals(8, binarySearch.search(8));Assertions.assertEquals(0, binarySearch.search(0));Assertions.assertEquals(9, binarySearch.search(9));}
}