Added day14 and day15 solution

Author: avidLearnerInProgress

30-days-of-code-may/14.maxCircularSumArray.cpp

@@ -0,0 +1,32 @@
+class Solution {
+public:
+    int maxSubarraySumCircular(vector<int>& A) {
+        if(A.size() == 0) return 0;
+        
+        int nocircle = helper(A), sum = 0;
+        if(nocircle < 0) return nocircle;
+        
+        auto t = A;
+        for(auto &n : t){
+            sum += n;
+            n *= -1;
+        }
+        
+        int circle = sum + helper(t);
+        return max(circle, nocircle);
+    }
+    
+    int helper(vector<int>& A){
+        if(A.size() == 0) return 0;
+        
+        int max_seen_so_far = INT_MIN, max_positive_seen = 0;
+        for(auto num : A){
+            if(max_positive_seen < 0)
+                max_positive_seen = num;
+            else
+                max_positive_seen += num;
+            max_seen_so_far = max(max_seen_so_far, max_positive_seen);
+        }
+        return max_seen_so_far;
+    }
+};

30-days-of-code-may/15.oddEvenNodes.cpp

@@ -0,0 +1,25 @@
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode(int x) : val(x), next(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    ListNode* oddEvenList(ListNode* head) {
+        if(!head) return NULL;
+        
+        auto odd = head, even_head = odd->next, even = even_head;
+        
+        while(even && even->next){
+            odd->next = odd->next->next;
+            even->next = even->next->next;
+            odd = odd->next;
+            even = even->next;
+        }
+        odd->next = even_head;
+        return head;
+    }
+};