Determine whether an integer is a palindrome. Do this without extra space.
Some hints:
Could negative integers be palindromes? (ie, -1)
If you are thinking of converting the integer to string, note the restriction of using extra space.
You could also try reversing an integer. However, if you have solved the problem “Reverse Integer”, you know that the reversed integer might overflow. How would you handle such case?
There is a more generic way of solving this problem.
public boolean isPalindrome(int x) {
if (x < 0)
return false;
int m = x;
int reverseNum = 0;
int temp = 0;
while (x != 0) {
temp = reverseNum * 10 + x % 10;
x = x / 10;
if (temp / 10 != reverseNum) {
reverseNum = 0;
break;
}
reverseNum = temp;
}
if (m == reverseNum)
return true;
else return false;
}
我就是用的Reverse Integer的方法,不过它上面说了There is a more generic way of solving this problem。我还没发现,希望哪位热心网友知道的话就告诉我哈。