Create number-of-distinct-averages.cpp

Author: kamyu104

C++/number-of-distinct-averages.cpp

@@ -0,0 +1,15 @@
+// Time:  O(nlogn)
+// Space: O(n)
+
+// sort, two pointers, hash table
+class Solution {
+public:
+    int distinctAverages(vector<int>& nums) {
+        sort(begin(nums), end(nums));
+        unordered_set<int> lookup;
+        for (int left = 0, right = size(nums) - 1; left < right; ++left, --right) {
+            lookup.emplace(nums[left] + nums[right]);
+        }
+        return size(lookup);
+    }
+};