LeetCode:33 搜索旋转排序数组（二分搜索）

class Solution {

    public int binary_search(int[]nums,int left,int right,int target){
        int mid=0;
        while(left<=right){
            mid = (left+right)/2;
            if(nums[mid]>target){
                right=mid-1;
            }
            else if(nums[mid]<target){
                left=mid+1;
            }
            else{
                return mid;
            }
        }

        if(nums[mid]!=target){
            return -1;
        }
        else{
            return mid;
        }
    }

    public int search(int[] nums, int target) {
        int n = nums.length;
        if(n==0){
            return -1;
        }
        if(n==1){
            return nums[0]==target?0:-1;
        }

        int mid=0;
        boolean flag=false;
        for(int i=1;i<n;i++){
            if(nums[i-1]>nums[i]){
                mid = i-1;
                flag=true;
                break;
            }
        }
        if(flag==false){
            mid=n-1;
        }
        if(target>=nums[0]&&target<=nums[mid]){
        
           return binary_search(nums,0,mid,target);
        }
        else{
            return binary_search(nums,mid+1,n-1,target);
        }
    }
}