Search for a Range
Given an array of integers sorted in ascending order, find the starting and ending position of a given target value.
Your algorithm's runtime complexity must be in the order of O(log n).
If the target is not found in the array, return [-1, -1].
For example, Given [5, 7, 7, 8, 8, 10] and target value 8, return [3, 4].
Solution
public class Solution {
public int[] searchRange(int[] nums, int target) {
int position = binarySearch(nums, target, 0, nums.length - 1);
if (position == -1)
return new int[]{-1, -1};
List<Integer> result = new ArrayList<Integer>();
int i = position;
while (i >= 0 && nums[i] == target) {
result.add(i);
i--;
}
int j = position;
while (j <= nums.length - 1 && nums[j] == target) {
result.add(j);
j++;
}
int[] resultA = new int[2];
resultA[0] = i + 1;
resultA[1] = j - 1;
return resultA;
}
public static int binarySearch(int[] nums, int target, int low, int high) {
if (low <= high) {
int middle = (low + high) / 2;
if (nums[middle] == target)
return middle;
if (target >= nums[low] && target < nums[middle]) {
return binarySearch(nums, target, low, middle - 1);
}
if (target <= nums[high] && target > nums[middle])
return binarySearch(nums, target, middle + 1, high);
}
return -1;
}
}