diff --git a/README.md b/README.md
index 61e1637..592900a 100644
--- a/README.md
+++ b/README.md
@@ -138,6 +138,7 @@ LeetCode solutions with Chinese explanation. LeetCode中文题解。
 | 191 |[Number of 1 Bits](https://leetcode.com/problems/number-of-1-bits)|[C++](https://github.com/ShusenTang/LeetCode/blob/master/solutions/191.%20Number%20of%201%20Bits.md)|Easy|  |
 | 198 |[House Robber](https://leetcode.com/problems/house-robber)|[C++](https://github.com/ShusenTang/LeetCode/blob/master/solutions/198.%20House%20Robber.md)|Easy|  |
 | 199 |[Binary Tree Right Side View](https://leetcode.com/problems/binary-tree-right-side-view/)|[C++](https://github.com/ShusenTang/LeetCode/blob/master/solutions/199.%20Binary%20Tree%20Right%20Side%20View.md)|Medium|  |
+| 200 |[Number of Islands](https://leetcode.com/problems/number-of-islands/)|[C++](https://github.com/ShusenTang/LeetCode/blob/master/solutions/200.%20Number%20of%20Islands.md)|Medium|  |
 | 202 |[Happy Number](https://leetcode.com/problems/happy-number)|[C++](https://github.com/ShusenTang/LeetCode/blob/master/solutions/202.%20Happy%20Number.md)|Easy|  |
 | 203 |[Remove Linked List Elements](https://leetcode.com/problems/remove-linked-list-elements)|[C++](https://github.com/ShusenTang/LeetCode/blob/master/solutions/203.%20Remove%20Linked%20List%20Elements.md)|Easy|  |
 | 204 |[Count Primes](https://leetcode.com/problems/count-primes)|[C++](https://github.com/ShusenTang/LeetCode/blob/master/solutions/204.%20Count%20Primes.md)|Easy|  |