Adding solution for 326

C++/326.cpp

@@ -0,0 +1,32 @@
+#include <iostream>
+#include <cstdint>
+#include <cmath>
+
+class Solution {
+public:
+    bool isPowerOfThree(int n) {
+        if ( n <= 0 ) { return false; }
+        if ( n == 1 ) { return true; }
+        for ( int i = 1; i < n; ++i ) {
+            long val = pow(3, i);
+            if ( val == n ) { return true; }
+            if ( val > n ) { return false; }
+        }
+        return false;
+    }
+};
+
+void r(int n, bool exp) {
+    std::cout << "Solution().isPowerOfThree(" << n << ") = ";
+    std::cout << Solution().isPowerOfThree(n);
+    std::cout << " | exp: " << exp << "\n";
+};
+
+int main(void) {
+    r(27, true);
+    r(9, false);
+    r(0, false);
+    r(-1, false);
+
+    return 0;
+}