Update valid-square.cpp

Author: kamyu104

C++/valid-square.cpp

@@ -4,10 +4,10 @@
 class Solution {
 public:
     bool validSquare(vector<int>& p1, vector<int>& p2, vector<int>& p3, vector<int>& p4) {
-        unordered_set<int> counter({ dist(p1, p2), dist(p1, p3),
-                                     dist(p1, p4), dist(p2, p3),
-                                     dist(p2, p4), dist(p3, p4) });
-        return !counter.count(0) && counter.size() == 2;
+        unordered_set<int> lookup({ dist(p1, p2), dist(p1, p3),
+                                    dist(p1, p4), dist(p2, p3),
+                                    dist(p2, p4), dist(p3, p4) });
+        return !lookup.count(0) && lookup.size() == 2;
     }
 
 private: