LeetCode-7. Reverse Integer

Description

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 1(C++)

class Solution {
public:
int reverse(int x) {
long res=0;
while(x!=0){
int a=x%10;
x/=10;
res=res*10+a;
}
return res>INT_MAX||res<INT_MIN ? 0 : res;
}
};

Solution 2(C++)

class Solution {
public:
int reverse(int x) {
int ans = 0;
while (x) {
int temp = ans * 10 + x % 10;
if (temp / 10 != ans)
return 0;
ans = temp;
x /= 10;
}
return ans;
}
};

算法分析

程序分析