Y总的模板太强大了，当初的我蛋疼地调了好久好久~~~

来看下实现：

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

        if (nums.length == 0) {
            return new int[]{-1, -1};
        }
        int[] ans = new int[2];
        int n = nums.length;
        int l = 0, r = n - 1;
        while (l < r){
            int mid = l + r >>> 1;
            // left
            if (nums[mid] >= target) r = mid;
            else l = mid + 1;
        }
        if (nums[l] != target) { 
            return new int[]{-1, -1};
        }
        ans[0] = l;
        l = 0;
        r = n - 1;
        while (l < r){
            int mid = l + r + 1 >>> 1;
            // right
            if (nums[mid] <= target) l = mid;
            else r = mid - 1;
        }
        ans[1] = r;
        return ans;
    }
}