public class Solution {

// 时间要求log(n)，显然是2次二分查找变形

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

// 首先判断不合理和不可能的情况

if (nums == null

|| nums.length == 0

|| target < nums[0]

|| target > nums[nums.length - 1]) return new int[] {-1, -1};

int left = 0, right = 0;

int len = nums.length;

int l = 0, r = len - 1;

// 寻找小于等于target的即left

int mid = 0;

while (l <= r) {

mid = (l + r) / 2;

if (nums[mid] < target) l = mid + 1;

else r = mid - 1;

}

left = l;

l = 0;

r = len - 1;

while (l <= r) {

mid = (l + r) / 2;

if (nums[mid] > target) r = mid - 1;

else l = mid + 1;

}

right = r;

// 判断是否找到

if (left < len && nums[left] == target) {

return new int[] {left, right};

}

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

}

}