Replaces String concatenation with StringBuilder

company/adobe/MajorityElement.java

@@ -9,10 +9,11 @@ public int majorityElement(int[] nums) {
 
         HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();
         for(int current: nums) {
-            if(map.containsKey(current) && map.get(current) + 1 > nums.length / 2) {
-                return current;
-            } else if(map.containsKey(current)) {
-                map.put(current, map.get(current) + 1);
+            if (map.containsKey(current)) {
+                if (map.get(current) + 1 > nums.length / 2)
+                    return current;
+                else
+                    map.put(current, map.get(current) + 1);
             } else {
                 map.put(current, 1);
             }
@@ -21,4 +22,4 @@ public int majorityElement(int[] nums) {
         //no majority element exists
         return -1;
     }
-}
+}

company/apple/ReverseWordsInAString.java

@@ -6,12 +6,12 @@
 public class ReverseWordsInAString {
     public String reverseWords(String s) {
         String[] words = s.trim().split("\\s+");
-        String result = "";
+        if(words.length==1) return s;
+        StringBuilder sb = new StringBuilder();
         for(int i = words.length - 1; i > 0; i--) {
-            result += words[i] + " ";
+            sb.append(words[i]).append(" ");
         }
-
-        return result + words[0];
+        return sb.append(words[0]).toString();
     }
 }
 

company/bloomberg/ReverseWordsInAString.java

@@ -6,12 +6,12 @@
 public class ReverseWordsInAString {
     public String reverseWords(String s) {
         String[] words = s.trim().split("\\s+");
-        String result = "";
+        if(words.length==1) return s;
+        StringBuilder sb = new StringBuilder();
         for(int i = words.length - 1; i > 0; i--) {
-            result += words[i] + " ";
+            sb.append(words[i]).append(" ");
         }
-
-        return result + words[0];
+        return sb.append(words[0]).toString();
     }
 }
 

company/microsoft/ReverseWordsInAString.java

@@ -6,12 +6,12 @@
 public class ReverseWordsInAString {
     public String reverseWords(String s) {
         String[] words = s.trim().split("\\s+");
-        String result = "";
+        if(words.length==1) return s;
+        StringBuilder sb = new StringBuilder();
         for(int i = words.length - 1; i > 0; i--) {
-            result += words[i] + " ";
+            sb.append(words[i]).append(" ");
         }
-
-        return result + words[0];
+        return sb.append(words[0]).toString();
     }
 }
 

company/snapchat/ReverseWordsInAString.java

@@ -6,12 +6,12 @@
 public class ReverseWordsInAString {
     public String reverseWords(String s) {
         String[] words = s.trim().split("\\s+");
-        String result = "";
+        if(words.length==1) return s;
+        StringBuilder sb = new StringBuilder();
         for(int i = words.length - 1; i > 0; i--) {
-            result += words[i] + " ";
+            sb.append(words[i]).append(" ");
         }
-
-        return result + words[0];
+        return sb.append(words[0]).toString();
     }
 }
 

company/yelp/ReverseWordsInAString.java

@@ -6,12 +6,12 @@
 public class ReverseWordsInAString {
     public String reverseWords(String s) {
         String[] words = s.trim().split("\\s+");
-        String result = "";
+        if(words.length==1) return s;
+        StringBuilder sb = new StringBuilder();
         for(int i = words.length - 1; i > 0; i--) {
-            result += words[i] + " ";
+            sb.append(words[i]).append(" ");
         }
-
-        return result + words[0];
+        return sb.append(words[0]).toString();
     }
 }
 

cracking-the-coding-interview/chapter-one-arrays-and-strings/IsRotation.java

@@ -8,7 +8,7 @@ public boolean isRotation(String s1, String s2) {
 		/*check that s1 and s2 are equal length and not empty */
 		if(len == s2.length() && len > 0) {
 			/* concatenate s1 and s1 within new buffer */
-			String s1s1 = s1 + s1;
+			String s1s1 = new StringBuilder().append(s1).append(s2).toString();
 			return isSubstring(s1s1, s2);
 		}
 

leetcode/array/MajorityElement.java

@@ -9,10 +9,11 @@ public int majorityElement(int[] nums) {
 
         HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();
         for(int current: nums) {
-            if(map.containsKey(current) && map.get(current) + 1 > nums.length / 2) {
-                return current;
-            } else if(map.containsKey(current)) {
-                map.put(current, map.get(current) + 1);
+            if (map.containsKey(current)) {
+                if (map.get(current) + 1 > nums.length / 2)
+                    return current;
+                else
+                    map.put(current, map.get(current) + 1);
             } else {
                 map.put(current, 1);
             }

leetcode/string/ReverseWordsInAString.java

@@ -6,11 +6,12 @@
 public class ReverseWordsInAString {
     public String reverseWords(String s) {
         String[] words = s.trim().split("\\s+");
-        String result = "";
+        if(words.length==1) return s;
+        StringBuilder sb = new StringBuilder();
         for(int i = words.length - 1; i > 0; i--) {
-            result += words[i] + " ";
+            sb.append(words[i]).append(" ");
         }
-
-        return result + words[0];
+        return sb.append(words[0]).toString();
     }
 }
+