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