Find Minimum in Rotated Sorted Array

package leetcode;
/* *
 * 注意问题：
 * 1. 原序列升序、降序问题，两种情况都要考虑
 * 2. 边界问题，如果只有两个元素时要单独考虑，在num[mid]==num[left]判断中考虑
 * 3. 采用2叉查找的思想
 * */
public class findMinInRotatedSortedArray {
    public int findMin(int[] num)
    {
        
        int left=0;
        int right=num.length-1;
        if(num[left]>num[right])//原序列是升序排列
        {
            while(left < right)
            {
                int mid=(left+right)/2;
                if(num[mid]==num[left])
                    left=mid+1;
                else if(num[mid]>num[left])
                    left=mid;
                else 
                    right=mid;
                
            }
        }
        else //原序列是降序排列
        {
            while(left < right)
            {
                int mid=(left+right)/2;
                if(num[mid]==num[left])
                    right=mid-1;
                else if(num[mid]>=num[left])
                    right=mid;
                else 
                    left=mid;    
            }
        }
        return num[left];
    }
    public static void main(String[] args)
    {
        int[] arr=new int[3];
        arr[0]=3;
        arr[1]=1;
        arr[2]=2;
        findMinInRotatedSortedArray a=new findMinInRotatedSortedArray();
        System.out.println(a.findMin(arr));
    }
}