二分查找（递归&非递归）java

二分查找（递归&非递归）java

package Test;

public class binarysearch {
    //二分查找，递归实现

    public static int binarysearch(int[] arr, int val) {
        int left = 0;
        int right = arr.length - 1;
        while (left <= right) {
            int mid = (left + right) / 2;
            if (arr[mid] == val) {
                return mid;
            } else if (arr[mid] > val) {
                right = mid - 1;
            } else {
                left= mid+ 1;
            }
        }
        return -1;
    }

    //二分查找 非递归实现
    public static int Rebinarysearch(int[] arr, int val) {
        return Rebinarysearch(arr, 0, arr.length - 1, val);

    }

    public static int Rebinarysearch(int[] arr, int left, int right, int val) {

        if (left > right) {
            return -1;
        }
        int mid = (left + right) / 2;
        if (arr[mid] == val) {
            return mid;
        } else if (arr[mid] > val) {
            return Rebinarysearch(arr, left, mid-1, val);
        } else {
            return Rebinarysearch(arr, mid+1, right, val);

        }
    }

    public static void main(String[] args) {
        int[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
        System.out.println("递归查找的索引位置分别为：");
        System.out.println(binarysearch(arr, 5));
        System.out.println(binarysearch(arr, 1));
        System.out.println(binarysearch(arr, 10));
        System.out.println(binarysearch(arr, 12));
        System.out.println("******************************");
        System.out.println("非递归查找的索引位置分别为：");
        System.out.println(Rebinarysearch(arr,6));
        System.out.println(Rebinarysearch(arr,12));
        System.out.println(Rebinarysearch(arr,10));
        System.out.println(Rebinarysearch(arr,3));
    }
}

"C:\Program Files (x86)\Java\jdk1.8.0_172\bin\java.exe" -javaagent:D:\ideaIU-2018.1.5.win\lib\idea_rt.jar=65181:D:\ideaIU-2018.1.5.win\bin -Dfile.encoding=UTF-8 -classpath "C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\charsets.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\deploy.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\ext\access-bridge-32.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\ext\cldrdata.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\ext\dnsns.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\ext\jaccess.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\ext\jfxrt.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\ext\localedata.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\ext\nashorn.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\ext\sunec.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\ext\sunjce_provider.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\ext\sunmscapi.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\ext\sunpkcs11.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\ext\zipfs.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\javaws.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\jce.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\jfr.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\jfxswt.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\jsse.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\management-agent.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\plugin.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\resources.jar;C:\Program Files (x86)\Java\jdk1.8.0_172\jre\lib\rt.jar;D:\TestDemo\out\production\TestDemo" Test.binarysearch
递归查找的索引位置分别为：
4
0
9
-1
******************************
非递归查找的索引位置分别为：
5
-1
9
2

Process finished with exit code 0

本人才疏学浅，如有错误，烦请指出，谢谢！