/
028_TurningNumber.java
69 lines (58 loc) · 1.87 KB
/
028_TurningNumber.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
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
// Coding Interviews: Questions, Analysis & Solutions
// Harry He
public class TurningNumber {
public static int getTurningIndex(int numbers[]) {
if(numbers.length <= 2)
return -1;
int left = 0;
int right = numbers.length - 1;
while(right > left + 1) {
int middle = (left + right) / 2;
if(middle == 0 || middle == numbers.length - 1)
return -1;
if(numbers[middle] > numbers[middle - 1]
&& numbers[middle] > numbers[middle + 1])
return middle;
else if(numbers[middle] > numbers[middle - 1]
&& numbers[middle] < numbers[middle + 1])
left = middle;
else
right = middle;
}
return -1;
}
//================= Test Code =================
private static void test(String testName, int[] numbers, int expected) {
System.out.print(testName + " begins: ");
if(getTurningIndex(numbers) == expected)
System.out.print("passed.\n");
else
System.out.print("FAILED.\n");
}
private static void test1() {
int numbers[] = {1, 2, 3, 4, 5, 10, 9, 8, 7, 6};
int expected = 5;
test("test1", numbers, expected);
}
private static void test2() {
int numbers[] = {1, 10, 9, 8, 7, 6, 5, 4, 3, 2};
int expected = 1;
test("test2", numbers, expected);
}
private static void test3() {
int numbers[] = {1, 2, 3, 4, 5, 6, 7, 8, 10, 9};
int expected = 8;
test("test3", numbers, expected);
}
private static void test4() {
int numbers[] = {1, 2, 1};
int expected = 1;
test("test4", numbers, expected);
}
public static void main(String args[]) {
test1();
test2();
test3();
test4();
}
}