longest palindrome - facebook code lab - merge two for loops - using array to iterate line 31, 32, line 34, line 35

longestPalindrome2B.java

/**
 * 
 */
/**
 * @author jchen
 *
 */
package test;

public class testing{
	
	public static void main(String[] args) {
	// TODO Auto-generated method stub

		String test = longestPalindrome("abb"); 
		System.out.print(test);
	}


	public static String longestPalindrome(String a) {
	    if(a==null)
	        return ""; 
	    int len = a.length(); 
	    
	   
	    int maxLength = 0; 
	    String res = "";
	    	    
	    for(int i=0; i< len;i++)
	    {
	        String s1 = getPalindromeLenC(a, i); 
	        String s2 = getPalindromLenR(a,i); 
	        
	        String[] arr = new String[]{s1, s2}; 
	        
	        for(String s : arr)
	        {
	        	int newOne = s.length(); 
	        	boolean update = newOne > maxLength; 
	        	maxLength = update? newOne : maxLength; 
	        	res = update? s : res;
	        }
	    }  
	   	    
	    return res; 
	}
	
	/* abcba style, center position is char c */
	public static String getPalindromeLenC(String s, int index)
	{
	    int len = s.length(); 
	    
	    int span = 1; 
	    while((index + span) < len && (index-span) >=0)
	    {
	        if(s.charAt(index+span) == s.charAt(index-span))
	           span++; 
	        else
	           break; 
	    }
	    
	    return s.substring(index-span +1, index+span -1); 
	}
	
	/*abba style, center position is first b */
	public static String getPalindromLenR(String s, int index)
	{
	    int len = s.length(); 
	    
	    int begin =index; 
	    int end = index +1; 
	    
	    boolean hasOne = false; 
	    while(begin >= 0 && end < len)  // len, not len-1
	    {
	        if(s.charAt(begin) == s.charAt(end))
	        {
	            hasOne = true; 
	            begin --; 
	            end ++; 
	        } 
	        else
	          break; 
	    }
	    
	    return (hasOne)? s.substring(begin+1, end):""; 
	}
}