蓝桥杯软件学院：常见算法之二分查找

Posted 2021-04-10 蓝桥杯

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今天蓝桥杯软件学院郑老师为大家分享常见算法之二分查找，希望大家能够喜欢：

1. public class ArraySort

2. {

4. //........这里省略了很多代码，请参考hi.baidu.com/alex_bw/blog/item/b817682041ec5348ac34de67.html中所示范的排序

5. private static int binarySearch0(int[] a, int fromIndex, int toIndex,

6. int key)

7. {

8. int low = fromIndex;

9. int high = toIndex - 1;

11. while (low <= high)

12. {

13. int mid = (low + high) >>> 1;

14. int midVal = a[mid];

16. if (midVal < key)

17. low = mid + 1;

18. else if (midVal > key)

19. high = mid - 1;

20. else

21. return mid; // key found

22. }

23. return -(low + 1); // key not found.

24. }

26. public static void main(String[] args)

27. {

28. int[] x =

29. { 49, 38, 65, 97, 76, 13, 27, 12, 18, 54, 20, 9, 8, 5, 6 };

30. System.out.println("begin..." + Arrays.toString(x));

31. // maopao(x, 0, x.length);

32. // xuanze(x, 0, x.length);

33. // charu(x, 0, x.length);

34. kuaisu(x, 0, x.length);

35. System.out.println("final..." + Arrays.toString(x));

36. int index = binarySearch0(x, 0, x.length - 1, 27);

37. System.out.println(index);

38. }

39. }

如果大家还不明白的话，欢迎大家参加蓝桥杯软件学院的免费实训计划。

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