如何判断一个字符串是否是回文？

Question

如何测试给定的 String 是否是 Java 中的回文，而不使用任何为我完成这一切的方法？

Answer 1

String palindrome = "..." // from elsewhere
boolean isPalindrome = palindrome.equals(new StringBuilder(palindrome).reverse().toString());

Answer 2

public boolean checkPalindrome(string word){

for(int i=0 ; i < word.length()/2;i++)
{
  if(word.charAt(i) ! = word.charAt(word.length()-1-i))

      return false;
}

return true;
}

Answer 3

诺埃尔的解决方案实际上更好。但如果是为了家庭作业，你可能想要这样做：

public static boolean isPalindrome(String word) {
    int left = 0;
    int right = word.length() -1;

    while (left < right) {
        if (word.charAt(left) != word.charAt(right)) 
            return false;

        left++;
        right--;
    }

    return true;
}

Answer 4

Java 就地回文检查：

public static final boolean isPalindromeInPlace(String string) {
    char[] array = string.toCharArray();
    int length = array.length-1;
    int half = Math.round(array.length/2);
    char a,b;
    for (int i=length; i>=half; i--) {
        a = array[length-i];
        b = array[i];
        if (a != b) return false;
    }
    return true;
}

Answer 5

String str="iai";

StringBuffer sb=new StringBuffer(str);
String str1=sb.reverse().toString();
if(str.equals(str1)){
   System.out.println("polindrom");
} else {
   System.out.println("not polidrom");
}