diff --git a/leetcode/README.md b/leetcode/README.md
index bb893c14..554b7117 100644
--- a/leetcode/README.md
+++ b/leetcode/README.md
@@ -52,6 +52,7 @@ LeetCode
 |215|[Kth Largest Element in an Array](https://leetcode.com/problems/kth-largest-element-in-an-array/) | [C](./src/215.c)|Medium|
 |217|[Contains Duplicate](https://leetcode.com/problems/contains-duplicate/) | [C](./src/217.c)|Easy|
 |226|[Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree/) | [C](./src/226.c)|Easy|
+|231|[Power of Two](https://leetcode.com/problems/power-of-two/) | [C](./src/231.c)|Easy|
 |234|[Palindrome Linked List](https://leetcode.com/problems/palindrome-linked-list/) | [C](./src/234.c)|Easy|
 |268|[Missing Number](https://leetcode.com/problems/missing-number/) | [C](./src/268.c)|Easy|
 |278|[First Bad Version](https://leetcode.com/problems/first-bad-version/) | [C](./src/278.c)|Easy|
diff --git a/leetcode/src/231.c b/leetcode/src/231.c
new file mode 100644
index 00000000..9957102f
--- /dev/null
+++ b/leetcode/src/231.c
@@ -0,0 +1,5 @@
+bool isPowerOfTwo(int n){
+    if (! n) return false;
+    while (n % 2 == 0) n /= 2;
+    return n == 1;
+}
\ No newline at end of file