leetcode [33] Search in Rotated Sorted Array

class Solution {
private:
    int searchCore(vector<int>nums,int begin,int end,int target){
        if(begin>end||begin<0||end>=nums.size()) return -1;
        if(nums[begin]==nums[end] && nums[begin]==target) return begin;
        if(nums[begin]<=nums[end]&&(nums[begin]>target||nums[end]<target)) return -1;        
        int mid=(end-begin)/2+begin;
        int l=searchCore(nums,begin,mid,target);
        int r=searchCore(nums,mid+1,end,target);
        if(l!=-1) return l;
        else return r;
    }

public:
    int search(vector<int>& nums, int target) {
        int res=-1;
        res=searchCore(nums,0,nums.size()-1,target);
        return res;
    }
};