Update 767_Reorganize_String.java

Author: Sean Prashad

Top K Elements/767_Reorganize_String.java

@@ -1,38 +1,45 @@
 class Solution {
     public String reorganizeString(String S) {
         if (S == null || S.length() == 0) {
-            return "";
+            return new String();
         }
 
-        HashMap<Character, Integer> hm = new HashMap<>();
-        PriorityQueue<int[]> pq = new PriorityQueue<>((a, b) -> b[1] - a[1]);
+        Map<Character, Integer> hm = new HashMap<>();
+        char maxChar = S.charAt(0);
 
         for (char c : S.toCharArray()) {
             hm.put(c, hm.getOrDefault(c, 0) + 1);
 
-            if (hm.get(c) > (S.length() + 1) / 2) {
-                return "";
+            if (hm.get(c) > hm.get(maxChar)) {
+                maxChar = c;
             }
         }
 
-        for (char key : hm.keySet()) {
-            pq.offer(new int[] { key, hm.get(key) });
+        if (hm.get(maxChar) > (S.length() + 1) / 2) {
+            return "";
         }
 
-        StringBuilder sb = new StringBuilder();
-        int[] prev = new int[] { -1, 0 };
+        int idx = 0;
+        char[] result = new char[S.length()];
 
-        while (!pq.isEmpty()) {
-            int[] curr = pq.poll();
+        while (idx < S.length() && hm.get(maxChar) > 0) {
+            result[idx] = maxChar;
+            idx += 2;
+            hm.put(maxChar, hm.get(maxChar) - 1);
+        }
 
-            if (--prev[1] > 0) {
-                pq.offer(prev);
-            }
+        for (char c : hm.keySet()) {
+            while (hm.get(c) > 0) {
+                if (idx >= S.length()) {
+                    idx = 1;
+                }
 
-            sb.append((char) curr[0]);
-            prev = curr;
+                result[idx] = c;
+                idx += 2;
+                hm.put(c, hm.get(c) - 1);
+            }
         }
 
-        return sb.toString();
+        return String.valueOf(result);
     }
 }