"Leetcode-Interview algorithm classic-java Implementation" "125-valid palindrome (back to text verification)"

"125-valid palindrome (back to text verification)" "leetcode-Interview algorithm classic-java Implementation" "All topics Directory Index" Original 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.
　　Note:
Are you consider that the string might is empty? This was a good question to ask during a interview.
For the purpose of this problem, we define empty string as valid palindrome.

Main Topic

Given a string, determine whether it is a palindrome string, consider only letters, and ignore case.

Thinking of solving problems

Using the end-to-end pointers, find the first qualifying position, compare them, and if they do the next set of comparisons, the unequal returns false until all the letters are processed.

Code Implementation

Algorithm implementation class

 Public  class solution {     Public Boolean Ispalindrome(String s) {if(s = =NULL) {return false; }intleft =0;intright = S.length ()-1;intDelta =' A '-' A ';CharLCharR while(Left < right) { while(Left < S.length () &&!isalphanumericcharacters (S.charat (left))) {//Find numbers and letters from left to rightleft++; } while(Right >=0&&!isalphanumericcharacters (S.charat (right))) {//Find numbers and letters from right to leftright--; }if(Left < right)                {L = S.charat (left); R = S.charat (right);if(L = = r | | l-r = = Delta | | r-l = = Delta)                    {left++;                right--; }Else{return false; }            }        }return true; }/** * Determine if it is a letter or a number * @param c number to be judged * @return Judging result * *    Private Boolean isalphanumericcharacters(Charc) {returnC >=' 0 '&& C <=' 9 '|| C >=' A '&& C <=' Z '|| C >=' A '&& C <=' Z '; }}

Evaluation Results

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"Leetcode-Interview algorithm classic-java Implementation" "125-valid palindrome (back to text verification)"