Create count-number-of-teams.cpp

Author: kamyu104

C++/count-number-of-teams.cpp

@@ -0,0 +1,22 @@
+// Time:  O(n^2)
+// Space: O(1)
+
+class Solution {
+public:
+    int numTeams(vector<int>& rating) {
+        int result = 0;
+        for (int i = 1; i < rating.size() - 1; ++i) {
+            vector<int> less(2), greater(2);
+            for (int j = 0; j < rating.size(); ++j) {
+                if (rating[i] > rating[j]) {
+                    ++less[i < j];
+                }
+                if (rating[i] < rating[j]) {
+                    ++greater[i < j];
+                }
+            }
+            result += less[0] * greater[1] + greater[0] * less[1];
+        }
+        return result;
+    }
+};