题目

法1：二分查找，最佳解法！！！

class Solution {public int[] searchRange(int[] nums, int target) {if (nums.length == 0) {return new int[]{-1, -1};}int n = nums.length;int left = findLeftBoundary(nums, target, 0, n - 1);int right = findRightBoundary(nums, target, 0, n - 1);if (left <= right) {return new int[]{left, right};}return new int[]{-1, -1};}public int findLeftBoundary(int[] nums, int target, int start, int end) {while (start <= end) {int mid = start + (end - start) / 2;if (nums[mid] >= target) {end = mid - 1;} else {start = mid + 1;}}return start;}public int findRightBoundary(int[] nums, int target, int start, int end) {while (start <= end) {int mid = start + (end - start) / 2;if (nums[mid] <= target) {start = mid + 1;} else {end = mid - 1;}}return end;}
}