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LeetCode_125. Valid Palindrome
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125. Valid Palindrome
Easy
Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.
Note: For the purpose of this problem, we define empty string as valid palindrome.
Example 1:
Input: "A man, a plan, a canal: Panama"
Output: true
Example 2:
Input: "race a car"
Output: false
package leetcode.easy;
public class ValidPalindrome {
@org.junit.Test
public void test() {
System.out.println(isPalindrome("A man, a plan, a canal: Panama"));
System.out.println(isPalindrome("race a car"));
}
public boolean isPalindrome(String s) {
s = s.trim().toLowerCase();
char[] chs = s.toCharArray();
int count = 0;
for (int i = 0; i < chs.length; i++) {
if ((chs[i] >= '0' && chs[i] <= '9') || (chs[i] >= 'a' && chs[i] <= 'z')) {
chs[count] = chs[i];
count++;
}
}
for (int i = 0; i < count / 2; i++) {
if (chs[i] != chs[count - i - 1]) {
return false;
}
}
return true;
}
}
