-
Notifications
You must be signed in to change notification settings - Fork 0
/
Reverse Integer
74 lines (66 loc) · 1.45 KB
/
Reverse Integer
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
70
71
72
73
74
/*
LeetCode 7:
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 hold integers within the 32-bit signed integer range. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.
Solution:
Language: C++
Tag:
*/
class Solution {
public:
int reverse(int x) {
/*
// 1. use long
long num = (long)x;
bool flag = true;
if (num < 0) {
flag = false;
num *= -1;
}
long res = 0;
while (num != 0) {
res = res * 10 + (num % 10);
num /= 10;
}
if (flag == false) {
res *= -1;
}
if (res < INT_MIN || res > INT_MAX) {
return 0;
}
return (int)res;
*/
// 2.
if (x == INT_MIN) {
return 0;
}
bool flag = true;
if (x < 0) {
flag = false;
x *= -1;
}
int res = 0;
while (x != 0) {
int tmp = res * 10 + (x % 10);
if ((tmp - (x % 10)) / 10 != res) {
return 0;
}
res = tmp;
x /= 10;
}
if (flag == true) {
return res;
}
return (res * -1);
}
};