Update OA 1 Question 1.java

Author: ChenHCY

Amazon OA/OA 1 Question 1.java

@@ -1,14 +1,21 @@
 /* Question 1:
+
 Change a String format be palindrome, need follow the alphabetical order
 
-Example: 
+Example 1: 
 Input: "xyxy"
 Output: "xyyx"
+
+Example 2:
+Input: "aaabbbbbcccc"
+Output: "abbccabccbba"
+
 */
+
 //Solution 1: Used bucket to sort and save element
 public class MyClass {
     public static void main(String args[]) {
-      String str = "xyxy";
+      String str = "aaabbbbbcccc";
       System.out.println(reverse(str));
     }
 
@@ -28,20 +35,24 @@ public static String reverse(String s){
       //Use bucket to sort String to be palindrome 
         for(int i = 0; i < array.length; i++){
             if(array[i] != 0){ //need check whether have this character element
-                if(array[i] % 2 == 0){ //if the number of current character is even
+                if(array[i] % 2 == 0){ //if the number of current character is even times
                     for(int k = 0; k < (array[i] / 2); k++){
                         firstPart.append((char) (i + 'a')); //add half part of current character into firstPart StringBuilder
                     }
-                } else{ //if the number of current character is odd
-                    for(int z = 0; z < array[i]; z++){
+                } else { //if the number of current character is odd times
+                    if(array[i] > 1){ // if the odd times is large than 1
+                        mid.append((char) (i + 'a')); // add one time into mid part StringBuilder
+                        for(int z = 0; z < array[i] / 2 ; z++){
+                            firstPart.append((char) (i + 'a')); //add half part of (character times - 1) into firstpart StringBuilder
+                        }
+                    } else{ //if the odd times is one
                         mid.append((char) (i + 'a')); //add all the number of current characters into mid Part
                     }
                 }
             }
         }
         //Output be palindrome format
         return firstPart.toString() + mid.toString() + firstPart.reverse().toString();
-        
     }
 }
 
@@ -52,7 +63,7 @@ public static String reverse(String s){
 
 public class MyClass {
     public static void main(String args[]) {
-      String str = "abbbaaa";
+      String str = "aaabbbbbcccc";
       System.out.println(reverse(str));
     }
 
@@ -74,15 +85,20 @@ public static String reverse(String s){
                     for(int k = 0; k < (number / 2); k++){
                         firstPart.append((char) (i + 'a')); //add half part of current character into firstPart StringBuilder
                     }
-                } else{ //if the number of current character is odd
-                    for(int z = 0; z < number; z++){
-                        mid.append((char) (i + 'a')); //add all the number of current characters into mid Part
+                } else{ //if the number of current character is odd times
+                    if(number > 1){ // if the odd times large than one 
+                        mid.append((char) (i + 'a')); //add one time of current characters into the mid Part StringBuilder
+                        for(int z = 0; z < number / 2; z++){
+                            firstPart.append((char) (i + 'a')); // /add half part of current character into firstPart StringBuilder
+                        }
+                    } else{
+                        mid.append((char) (i + 'a')); //add one time of current characters into mid Part
                     }
                 }
             }
         }
-        //Output be palindrome format
-        return firstPart.toString() + mid.toString() + firstPart.reverse().toString();
 
+        //Output be palindrome format
+        return firstPart.toString() + mid.toString() + firstPart.reverse().toString(); 
     }
 }