/
7.ReverseInteger.cpp
68 lines (65 loc) · 1.25 KB
/
7.ReverseInteger.cpp
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
/*
* @lc app=leetcode id=7 lang=cpp
*
* [7] Reverse Integer
*
* https://leetcode.com/problems/reverse-integer/description/
*
* algorithms
* Easy (25.82%)
* Likes: 3763
* Dislikes: 5883
* Total Accepted: 1.2M
* Total Submissions: 4.8M
* Testcase Example: '123'
*
* Given a 32-bit signed integer, reverse digits of an integer.
*
* Example 1:
*
*
* Input: 123
* Output: 321
*
*
* Example 2:
*
*
* Input: -123
* Output: -321
*
*
* Example 3:
*
*
* Input: 120
* Output: 21
*
*
* Note:
* Assume we are dealing with an environment which could only store integers
* within the 32-bit signed integer range: [−2^31, 2^31 − 1]. For the purpose
* of this problem, assume that your function returns 0 when the reversed
* integer overflows.
*
*/
// @lc code=start
#include <cmath>
class Solution {
public:
int reverse(int x) {
long rev = 0;
long copy = x;
bool is_negative = copy < 0;
copy = copy > 0 ? copy : -copy;
while (copy) {
rev *= 10;
rev += (copy % 10);
copy /= 10;
}
if (is_negative) rev = -rev;
if (rev < -1 * pow(2, 31) || rev > pow(2, 31) - 1) return 0;
return rev;
}
};
// @lc code=end