Leetcode Search for a range

Given a sorted array of integers, find the starting and ending position of a given target value.

Your algorithm’s runtime complexity must be in the order of O(log n).

If the target is not found in the array, return [-1, -1].

For example,
Given [5, 7, 7, 8, 8, 10] and target value 8,
return [3, 4].

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public class Solution {
    public int[] searchRange(int[] A, int target) {
        int[]r=new int[]{-1,-1};
        if(A==null || A.length==0)return r;
        int start=0, end=A.length-1,mid=(start+end)/2;
        while(start<=end)
        {
            mid=(start+end)/2;
            if(A[mid]==target)break;
            else if(A[mid]<target)start=mid+1;
            else end=mid-1;
        }
        if(start>end)return r;
        else
        {
            int t=mid-1;
            while(t>=0 && A[t]==target)t--;
            r[0]=t+1;
            t=mid+1;
            while(t<A.length && A[t]==target)t++;
            r[1]=t-1;
            return r;
        }
    }
}