Added valid anagram solution

Author: aishsingh

ValidAnagram/solution.cpp

@@ -0,0 +1,20 @@
+#include <unordered_map>
+
+class Solution {
+public:
+    bool isAnagram(string s, string t) 
+    {
+        // Use hashmap to keep count of letters in both strings
+        unordered_map<char, int> s1LetterCount;
+        unordered_map<char, int> s2LetterCount;
+
+        for (auto letter : s)
+            s1LetterCount[letter]++;
+
+        for (auto letter : t)
+            s2LetterCount[letter]++;
+
+        // The letter counts in each hashmap should match for the strings to be a valid anagram
+        return (s1LetterCount == s2LetterCount);
+    }
+};