给定一个按照升序排列的整数数组 nums，和一个目标值 target。找出给定目标值在数组中的开始位置和结束位置。
你的算法时间复杂度必须是 O(log n) 级别。
如果数组中不存在目标值，返回 [-1, -1]。
示例 1:
输入: nums = [5,7,7,8,8,10], target = 8
输出: [3,4]
示例 2:
输入: nums = [5,7,7,8,8,10], target = 6
输出: [-1,-1]
class Solution {
public int[] searchRange(int[] nums, int target) {
int[] result = new int[2];
int low = 0;
int high = nums.length - 1;
while(low <= high) {
int mid = (low + high) / 2;
if(nums[mid] == target) {
int start = startPosition(nums, mid);
int end = endPosition(nums, mid);
result[0] = start;
result[1] = end;
return result;
} else if(nums[mid] < target) {
low = mid + 1;
} else {
high = mid - 1;
}
}
result[0] = -1;
result[1] = -1;
return result;
}
private int startPosition(int[] nums, int curIndex) {
int start = curIndex-1;
while(start >= 0 && nums[start] == nums[curIndex]) {
start--;
}
return start+1;
}
private int endPosition(int[] nums, int curIndex) {
int end = curIndex+1;
while(end < nums.length && nums[end] == nums[curIndex]) {
end++;
}
return end-1;
}
}
