二分
class Solution {
public int[] searchRange(int[] nums, int target) {
int l = 0, r = nums.length - 1;
while(l < r){
int mid = l + r >> 1;
if(nums[mid] >= target) r = mid;
else l = mid + 1;
}
if(nums.length == 0 || nums[l] != target) return new int[]{-1, -1};
int start = l;
l = 0;
r = nums.length - 1;
while(l < r){
int mid = l + r + 1 >> 1;
if(nums[mid] > target) r = mid - 1;
else l = mid;
}
return new int[]{start, l};
}
}