forked from yuzhangcmu/LeetCode
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathFindPeakElement.java
More file actions
executable file
·66 lines (54 loc) · 1.58 KB
/
Copy pathFindPeakElement.java
File metadata and controls
executable file
·66 lines (54 loc) · 1.58 KB
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
53
54
55
56
57
58
59
60
61
62
63
64
65
66
package Algorithms.binarySearch;
public class FindPeakElement {
public int findPeakElement1(int[] num) {
if (num == null) {
return 0;
}
if (num.length == 1) {
return 0;
}
for (int i = 0; i < num.length; i++) {
if (i == 0) {
if (num[i] > num[i + 1]) {
return i;
}
continue;
}
if (i == num.length - 1) {
if (num[i] > num[i - 1]) {
return i;
}
continue;
}
if (num[i] > num[i + 1] && num[i] > num[i - 1]) {
return i;
}
}
return -1;
}
public int findPeakElement(int[] num) {
if (num == null) {
return 0;
}
if (num.length == 1) {
return 0;
}
int l = 0;
int r = num.length - 1;
while (l < r - 1) {
int mid = l + (r - l) / 2;
if (num[mid] > num[mid + 1] && num[mid] > num[mid - 1]) {
return mid;
}
if (num[mid] > num[mid - 1] && num[mid] < num[mid + 1]) {
// rising area. move right;
l = mid;
} else if (num[mid] < num[mid - 1] && num[mid] > num[mid + 1]) {
r = mid;
} else {
l = mid;
}
}
return num[l] > num[r] ? l: r;
}
}