main idea is simple:make two binary search for target-0.5 and target+0.5。make sure to check if target is exist

'''

public int[] searchRange(int[] nums, int target) {

int begin = binarySearch(nums,target-0.5);

int end = binarySearch(nums, target+0.5)-1;

if (begin<0||begin>nums.length-1||nums[begin]!=target){

return new int[]{-1,-1};

}

```
return new int[]{begin,end};
}
private int binarySearch(int[] nums, double target) {
int begin =0;
int end=nums.length-1;
while (begin<=end){
int mid=(begin+end)/2;
if (nums[mid]>target){
end=mid-1;
}else {
begin=mid+1;
}
}
return begin;
}
```

'''