题目:
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?
思路:这题比较简单,可以把数字翻转与原数进行比对。需要注意的是负数的判定以及翻转之后可能会产生溢出的问题。
public class Solution { public boolean isPalindrome(int x) { if(x<0) return false; long res=0; long lx=x; while(lx!=0){ res=res*10+lx%10; lx/=10; } return res==x; } }
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