Create 89. Gray Code.cpp

Author: ZengruiWang

89. Gray Code.cpp

@@ -0,0 +1,12 @@
+class Solution {
+public:
+    vector<int> grayCode(int n) {
+        vector<int> res;
+        res.push_back(0);
+        for(int i = 1, scale = 1; i <= n; ++i, scale *= 2){
+            for(int j = res.size() - 1; j >= 0; --j)
+                res.push_back(res[j] + scale);
+        }
+        return res;
+    }
+};