34. 在排序数组中查找元素的第一个和最后一个位置

class Solution {
    public int first=Integer.MAX_VALUE;
    public int end=Integer.MIN_VALUE;
    public int[] searchRange(int[] nums, int target) {
        if(nums==null||nums.length==0){
            return new int[]{-1,-1};
        }
        
        helper(nums,target,0,nums.length-1);
         
        if(first==Integer.MAX_VALUE){
           return new int[]{-1,-1};
        }
        
        if(end==Integer.MIN_VALUE){
            return new int[]{first,-1};
        }
          return new int[]{first  ,end};
    }
        public void helper(int [] nums,int target,int left,int right){
            if(left>right||left<0||right>=nums.length) return ;
            int mid=left+(right-left)/2;
            if(nums[mid]==target){
                    if(mid<first){
                        first=mid;
                       
                    }
                    if(mid>end){
                        end=mid;
                        
                    }

            }
            if(nums[mid]>=target){
                 helper(nums,target,left,mid-1);
            }
            if(nums[mid]<=target){
                 helper(nums,target,mid+1,right);
            }
            return;

        }
}