Create flip-columns-for-maximum-number-of-equal-rows.cpp

Author: kamyu104

C++/flip-columns-for-maximum-number-of-equal-rows.cpp

@@ -0,0 +1,28 @@
+// Time:  O(m * n)
+// Space: O(m * n)
+
+class Solution {
+public:
+    int maxEqualRowsAfterFlips(vector<vector<int>>& matrix) {
+        unordered_map<string,int> count;
+        for (const auto& row : matrix){
+            ++count[encode(row)]; 
+        }
+        
+        using pair_type = decltype(count)::value_type;
+        return max_element(count.cbegin(), count.cend(),
+                           [] (const pair_type& a,
+                               const pair_type& b) {
+                               return a.second < b.second;
+                           })->second;
+    }
+
+private:
+    string encode(const vector<int>& s) {
+        string result;
+        for (const auto& c : s) {
+            result.push_back(c ^ s[0]);
+        }
+        return result;
+    }
+};