Implement isPowerOfTwo function in Solution class

Author: Subhosjx

231. Power of Two.cpp

@@ -0,0 +1,7 @@
+class Solution {
+public:
+    bool isPowerOfTwo(int n) {
+        if (n <= 0) return false;
+        return (n & (n - 1)) == 0;
+    }
+};