1118

Author: surajr

README.md

@@ -27,6 +27,7 @@ Feel free to submit pull requests, add issues and be a contributer.
 |---------------- |---------------- | ----------- | --------------- | --------------- | ------------- |-----|
 | Careercup  | [Permutation Casewise](https://www.careercup.com/question?id=6255535581036544) | [Java](./java/PermuteCasewise.java)  | _O(2^n)_       | _O(1)_          |  Medium       |         |
 | Leetcode  | [50. Pow(x, n)](https://leetcode.com/problems/powx-n/description/) | [Java](./java/myPow.java)  | _O(n)_       | _O(1)_          |  Medium       |         |
+| Leetcode  | [89. Gray Code](https://leetcode.com/problems/gray-code/description/) | [Java](./java/grayCode.java)  | _O(n)_       | _O(1)_          |  Medium       |         |
 | Leetcode  | [137. Single Number II](https://leetcode.com/problems/single-number-ii/description/) | [Java](./java/singleNumberii.java)  | _O(n)_       | _O(1)_          |  Medium       |         |
 | Leetcode  | [190. Reverse Bits](https://leetcode.com/problems/reverse-bits/description/) | [Java](./java/reverseBits.java)  | _O(n)_       | _O(n)_          |  Easy       |         |
 | Leetcode  | [191. Number of 1 Bits](https://leetcode.com/problems/number-of-1-bits/description/) | [Java](./java/hammingWeight.java)  | _O(n)_       | _O(1)_          |  Easy       |         |
@@ -53,6 +54,7 @@ Feel free to submit pull requests, add issues and be a contributer.
 | Leetcode | [121. Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/description/) | [Java](./java/maxProfit.java)  | _O(n)_       | _O(1)_          |  Easy       |         |
 | Leetcode | [189. Rotate Array](https://leetcode.com/problems/rotate-array/description/) | [Java](./java/rotate.java)  | _O(n)_       | _O(1)_          |  Easy       |         |
 | Leetcode | [217. Contains Duplicate](https://leetcode.com/problems/contains-duplicate/description/) | [Java](./java/containsDuplicate.java)  | _O(n)_       | _O(1)_          |  Easy       |         |
+| Leetcode | [228. Summary Ranges](https://leetcode.com/problems/summary-ranges/description/) | [Java](./java/summaryRanges.java)  | _O(n)_       | _O(1)_          |  Medium       |         |
 | Leetcode | [311. Sparse Matrix Multiplication](https://leetcode.com/problems/sparse-matrix-multiplication/description/) | [Java](./java/sparseMultiply.java)  | _O(m*n*l)_       | _O(m*l)_          |  Medium       |         |
 | Leetcode | [350. Intersection of Two Arrays II](https://leetcode.com/problems/intersection-of-two-arrays-ii/description/) | [Java](./java/intersect.java)  | _O(m+n)_       | _O(1)_          |  Easy       |         |
 | Leetcode | [383. Ransom Note](https://leetcode.com/problems/ransom-note/description/) | [Java](./java/canConstruct.java)  | _O(n)_       | _O(1)_          |  Easy       |         |
@@ -249,6 +251,7 @@ Feel free to submit pull requests, add issues and be a contributer.
 | Leetcode  | [75. Sort Colors](https://leetcode.com/problems/sort-colors/description/) | [Java](./java/sortColors.java)  | _O(n)_       | _O(1)_          |  Medium       |         |
 | Leetcode  | [147. Insertion Sort List](https://leetcode.com/problems/insertion-sort-list/description/) | [Java](./java/insertionSortList.java)  | _O(nlogn)_       | _O(1)_          |  Medium       |         |
 | Leetcode  | [179. Largest Number](https://leetcode.com/problems/largest-number/description/) | [Java](./java/largestNumber.java)  | _O(nlogn)_       | _O(n)_          |  Medium       |         |
+| Leetcode  | [280. Wiggle Sort](https://leetcode.com/problems/wiggle-sort/description/) | [Java](./java/wiggleSort.java)  | _O(n)_       | _O(1)_          |  Medium       |         |
 
 ## Math
 | Website 		| Title           |  Solution    |  Time           | Space           | Difficulty    |  Note| 

java/grayCode.java

@@ -0,0 +1,8 @@
+class Solution {
+    public List<Integer> grayCode(int n) {
+        List<Integer> result = new ArrayList<>();
+        for(int i=0; i < 1<<n; i++)
+            result.add(i^i>>1);
+        return result;
+    }
+}

java/summaryRanges.java

@@ -0,0 +1,18 @@
+class Solution {
+    public List<String> summaryRanges(int[] nums) {
+        List<String> result = new ArrayList<>();
+        
+        for(int i=0; i<nums.length; i++)
+        {
+            int cur = nums[i];
+            while(i < nums.length-1 && nums[i]+1 == nums[i+1])
+                i++;
+            if(cur != nums[i])
+                result.add(cur + "->" + nums[i]);
+            else
+                result.add(cur+"");
+        }
+        
+        return result;
+    }
+}

java/wiggleSort.java

@@ -0,0 +1,21 @@
+class Solution {
+    public void wiggleSort(int[] nums) {
+        for(int i=0; i<nums.length; i++)
+        {
+            if(i%2 == 1)
+            {
+                if(nums[i] < nums[i-1])
+                    swap(nums, i);
+            }
+            else if(i != 0 && nums[i] > nums[i-1]) 
+                swap(nums, i);
+        }
+    }
+    
+    public void swap(int [] nums, int k)
+    {
+        int temp = nums[k];
+        nums[k] = nums[k-1];
+        nums[k-1] = temp;
+    }
+}