10/13

Author: surajr

BuddyStrings.java

@@ -0,0 +1,20 @@
+class Solution {
+    public boolean buddyStrings(String A, String B) {
+        if(A.length() != B.length()) return false;
+                
+        if(A.equals(B)){
+            Set<Character> set = new HashSet<>();
+            for(char c:A.toCharArray()) set.add(c);
+            return set.size() < A.length();
+        }
+        
+        List<Integer> diff = new ArrayList<>();
+        for(int i=0; i<A.length(); i++)
+            if(A.charAt(i) != B.charAt(i))
+                diff.add(i);
+        
+        return diff.size()<=2 && 
+            A.charAt(diff.get(0)) == B.charAt(diff.get(1)) && 
+            A.charAt(diff.get(1)) == B.charAt(diff.get(0));
+    }
+}

README.md

@@ -114,6 +114,9 @@ Feel free to submit pull requests, add issues and be a contributer.
 | Leetcode  | [647. Palindromic Substrings](https://leetcode.com/problems/palindromic-substrings/) | [Java](./java/CountSubstrings.java)  | _O(n^2)_       | _O(1)_          |  Easy       |         |
 | Leetcode  | [686. Repeated String Match](https://leetcode.com/problems/repeated-string-match/description/) | [Java](./java/repeatedStringMatch.java)  | _O(n)_       | _O(1)_          |  Easy       |         |
 | Leetcode  | [771. Jewels and Stones](https://leetcode.com/problems/jewels-and-stones/description/) | [Java](./java/numJewelsInStones.java)  | _O(n)_       | _O(1)_          |  Easy       |         |
+| Leetcode  | [848. Shifting Letters](https://leetcode.com/problems/shifting-letters/) | [Java](./java/shiftingLetters.java)  | _O(n)_       | _O(1)_          |  Medium       |         |
+| Leetcode  | [856. Score of Parentheses](https://leetcode.com/problems/score-of-parentheses/) | [Java](./java/scoreOfParenthesis.java)  | _O(n)_       | _O(n)_          |  Medium       |         |
+| Leetcode  | [859. Buddy Strings](https://leetcode.com/problems/buddy-strings/) | [Java](./java/BuddyStrings.java)  | _O(n)_       | _O(n)_          |  Easy       |         |
 
 
 ## HashMap

java/maximumProduct.java

@@ -8,6 +8,24 @@ public class Solution {
     max1 * max2 * max3 = 0
     min1 * min2 * max1 = -8 * -4 * 1 = 32 -> Return as answer
     */
+
+// Time O(NLogN) Space O(N) - Because of searching
+    public int maximumProduct(int[] nums) 
+    {
+        Arrays.sort(nums);
+        int len = nums.length - 1;
+        int end = nums[len-2] * nums[len-1] * nums[len];
+        int start = nums[0] * nums[1] * nums[len];
+        
+        return Math.max(end, start);
+    }
+}
+
+// Solution 2
+
+//Time O(N) Space O(1)
+public class Solution {
+    
     public int maximumProduct(int[] nums) 
     {
         int max1 = Integer.MIN_VALUE, max2 = Integer.MIN_VALUE, max3 = max1;