Description
Reverse digits of an integer.
Example
Example1: x = 123, return 321
Example2: x = -123, return -321
Note:
The input is assumed to be a 32-bit signed integer. Your function should return 0 when the reversed integer overflows.
Subscribe to see which companies asked this question.思路
- 这个题好像也没有什么简便方法，注意边界条件吧
代码
- 时间复杂度：O(m) m为输入数的有多少位
class Solution {
public:
const int max_int = 2147483647;
const int min_int = -2147483648;
int reverse(int x) {
if(x >= -9 && x <= 9) return x;
if(x == min_int || x == max_int) return 0;
vector<int> num(10, 0);
bool isNeg = false;
long long sum = 0;
int count = 0;
if(x < 0){
x = -x;
isNeg = true;
}
while(x){
num[count++] = x % 10;
x /= 10;
}
for(int i = 0; i < count; i++)
sum = sum * 10 + num[i];
if(sum > max_int){
if(isNeg && -sum == min_int) return min_int;
return 0;
}
return isNeg ? -sum : sum;
}
};内容来源于网络如有侵权请私信删除
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