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Palindrome Number
Description:
Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.
Example:
Example 1:
Input: 121 Output: true
Example 2:
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:
Input: 10 Output: false Explanation: Reads 01 from right to left. Therefore it is not a palindrome.
Follow up:
Coud you solve it without converting the integer to a string?
bool isPalindrome(int x)
{
std::vector<int> resultTemp; // 定义一个整型的vector 用来保存反转之后的数字序列
int result = 0,tempx = abs(x); // 定义结果变量以及临时保存x的绝对值
if(x<0)return false; // 小于0的数全部false
else if(x==0)return true; // 等于0 true
else if(x>0) // 大于0
{
do
{
resultTemp.push_back(x%10);
x=x/10;
}while(x!=0); // 用于反转数字,并将反转的数字序列保存在resultTemp中
for(int i =0;i<resultTemp.size();i++) // 将反转之后的数字序列组装成一个整数 保存在result中
{
result += resultTemp[i]*pow(10.,(int)resultTemp.size()-1-i);
}
if(result == tempx)return true; // 判断result 与 最初的x是否相等 相等返回true 否则返回false
else return false;
}
}