[Leetcode] Search in Rotated Sorted Array (Java)

Suppose a sorted array is rotated at some pivot unknown to you beforehand.

(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).

You are given a target value to search. If found in the array return its index, otherwise return -1.

You may assume no duplicate exists in the array.

循环数组查找，二分查找，几种情况分类讨论

public class SearchinRotatedSortedArray {public int search(int[] A, int target) {int res=-1;int low=0;int high=A.length-1;while(low<=high){int med = low+((high-low)>>1);if(A[med]==target)return med;else if(A[med]>target){if(A[high]>=A[med]){high=med-1;}else if(A[low]<=target){high=med-1;}else {low=med+1;}}else {if(A[low]<=A[med]){low=med+1;}else if(A[low]<=target){high=med-1;}else {low=med+1;}}}return res;}public static void main(String[] args) {int[] A = {1,3};int target= 3;System.out.println(new SearchinRotatedSortedArray().search(A, target));}}