Create count-common-words-with-one-occurrence.cpp

Author: kamyu104

C++/count-common-words-with-one-occurrence.cpp

@@ -0,0 +1,24 @@
+// Time:  O(m + n)
+// Space: O(m + n)
+
+class Solution {
+public:
+    int countWords(vector<string>& words1, vector<string>& words2) {
+        unordered_map<string, int> cnt;
+        for (const auto& w : words1) {
+            ++cnt[w];
+        }
+        for (const auto& w : words2) {
+            if (cnt[w] < 2) {
+                --cnt[w];
+            }
+        }
+        int result = 0;
+        for (const auto& [_, v] : cnt) {
+            if (v == 0) {
+                ++result;
+            }
+        }
+        return result;
+    }
+};