Valid Palindrome回文数

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Question:

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.

解决方法：使用两个指针，分别指向头尾，然后向中间移动依次判断

int isPalindrome(string s)

{

int i=0,j=s.size()-1;

if (j==0)

{

return 0;

}

while(i<j)

{

if (s[i++] != s[j--])

{

return 0;

}

}

return 1;

}