leetCode刷题(找到最长的回文字符串)

/**
 * @param {string} s
 * @return {string}
 */
var longestPalindrome = function(s) {
  var maxLength="";
  var maxPalindrome="";
  for(index=0;index<s.length;index++){
      var strOdd=getPalindromeLength(index,index,s);
      var strEven=getPalindromeLength(index,index+1,s);
      var strOddLength=strOdd.length;
      var strEvenLength=strEven.length;
      if(maxLength<strOddLength){
          maxLength=strOddLength;
          maxPalindrome=strOdd;
      }
      if(maxLength<strEvenLength){
          maxLength=strEvenLength;
          maxPalindrome=strEven;
      }
  }
  function getPalindromeLength(start,end,Palindrome){
      while((start>=0)&&(end<Palindrome.length)&&(Palindrome[start]==Palindrome[end])){
            start--;
            end++;
      }
      return Palindrome.substring(start+1,end);
  }
  return maxPalindrome
};