/
FindFirstAndLastElementsInSortedArray.java
52 lines (45 loc) · 1.49 KB
/
FindFirstAndLastElementsInSortedArray.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
// https://leetcode.com/problems/find-first-and-last-position-of-element-in-sorted-array/
class Solution {
public int[] searchRange(int[] nums, int target) {
return new int[] {
binarySearch(nums, target, 0),
binarySearch(nums, target, 1),
};
}
// 0 - left
// 1 - right
int binarySearch(int[] nums, int target, int direction) {
int low = 0, high = nums.length - 1;
while (low <= high) {
int mid = (low + high)/2;
if (nums[mid] == target) {
if (direction == 0) {
if (mid == 0) {
return mid;
}
if (nums[mid - 1] != target) {
return mid;
}
high = mid - 1;
} else if (direction == 1) {
if (mid == nums.length - 1) {
return mid;
}
if (nums[mid + 1] != target) {
return mid;
}
low = mid + 1;
} else {
return mid;
}
} else {
if (nums[mid] > target) {
high = mid - 1;
} else {
low = mid + 1;
}
}
}
return -1;
}
}