-
Notifications
You must be signed in to change notification settings - Fork 0
/
Solution.java
51 lines (47 loc) · 1.29 KB
/
Solution.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
package palindromenumber;
import java.util.ArrayList;
import java.util.List;
/**
* Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.
* <p>
* Example 1:
* <p>
* Input: 121
* Output: true
* Example 2:
* <p>
* Input: -121
* Output: false
* Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.
* Example 3:
* <p>
* Input: 10
* Output: false
* Explanation: Reads 01 from right to left. Therefore it is not a palindrome.
* Follow up:
* <p>
* Coud you solve it without converting the integer to a string?
*/
class Solution {
public boolean isPalindrome(int x) {
if (x < 0)
return false;
List<Integer> rev = new ArrayList<>();
int num = x;
while (num > 0) {
int last = num % 10;
rev.add(last);
num /= 10;
}
for (int i = 0, j = rev.size() - 1; i <= j; i++, j--) {
if (rev.get(i) != rev.get(j)) {
return false;
}
}
return true;
}
}
/*
Runtime: 8 ms, faster than 43.80% of Java online submissions for Palindrome Number.
Memory Usage: 40.7 MB, less than 5.02% of Java online submissions for Palindrome Number.
*/