LeetCode: Valid Palindrome

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LeetCode: Valid Palindrome

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.

For example,
"A man, a plan, a canal: Panama" is a palindrome.
"race a car" is not a palindrome.

Note:
Have you consider that the string might be empty? This is a good question to ask during an interview.

For the purpose of this problem, we define empty string as valid palindrome.

地址：https://oj.leetcode.com/problems/valid-palindrome/

算法：这道题应该可以直接上代码吧。

 1 class Solution {
 2 public:
 3     bool isPalindrome(string s) {
 4         int n = s.size();
 5         int j = 0;
 6         for(int i = 0; i < n; ++i){
 7             if(isalnum(s[i])){
 8                 s[j++] = tolower(s[i]);
 9             }
10         }
11         s = s.substr(0,j);
12         int len = j;
13         j = j / 2;
14         int i = 0;
15         while(i < j && s[i] == s[len - i - 1])  ++i;
16         return i == j;
17     }
18 };

LeetCode: Valid Palindrome

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原文地址：http://www.cnblogs.com/boostable/p/leetcode_valid_palindrome.html