add 988

Author: luliyucoordinate

Diff for: README.md

@@ -315,4 +315,5 @@ LeetCode
 |0982|[Triples with Bitwise AND Equal To Zero](https://leetcode.com/problems/triples-with-bitwise-and-equal-to-zero/) | c | [c++](./src/0982-Triples-with-Bitwise-AND-Equal-To-Zero/0982.cpp) |[python](./src/0982-Triples-with-Bitwise-AND-Equal-To-Zero/0982.py)|||Hard|
 |0983|[Minimum Cost For Tickets](https://leetcode.com/problems/minimum-cost-for-tickets/) | c | [c++](./src/0983-Minimum-Cost-For-Tickets/0983.cpp) |[python](./src/0983-Minimum-Cost-For-Tickets/0983.py)|||Medium|
 |0984|[String Without AAA or BBB](https://leetcode.com/problems/string-without-aaa-or-bbb/) | c | [c++](./src/0984-String-Without-AAA-or-BBB/0984.cpp) |[python](./src/0984-String-Without-AAA-or-BBB/0984.py)|||Easy|
-|0985|[Sum of Even Numbers After Queries](https://leetcode.com/problems/sum-of-even-numbers-after-queries/) | c | [c++](./src/0985-Sum-of-Even-Numbers-After-Queries/0985.cpp) |[python](./src/0985-Sum-of-Even-Numbers-After-Queries/0985.py)|||Easy|
+|0985|[Sum of Even Numbers After Queries](https://leetcode.com/problems/sum-of-even-numbers-after-queries/) | c | [c++](./src/0985-Sum-of-Even-Numbers-After-Queries/0985.cpp) |[python](./src/0985-Sum-of-Even-Numbers-After-Queries/0985.py)|||Easy|
+|0988|[Smallest String Starting From Leaf](https://leetcode.com/problems/smallest-string-starting-from-leaf/) | c | [c++](./src/0988-Smallest-String-Starting-From-Leaf/0988.cpp) |[python](./src/0988-Smallest-String-Starting-From-Leaf/0988.py)|||Easy|

Diff for: src/0988-Smallest-String-Starting-From-Leaf/0988.cpp

@@ -0,0 +1,15 @@
+#include <string>
+#include <vector>
+using namespace std;
+
+static int x = []() {std::ios::sync_with_stdio(false); cin.tie(0); return 0; }();
+class Solution 
+{
+public:
+    string smallestFromLeaf(TreeNode* r) 
+    {
+        if (r == nullptr) return "|";
+        auto s = string(1, 'a' + r->val);
+        return r->left == r->right ? s : min(smallestFromLeaf(r->left) + s, smallestFromLeaf(r->right) + s);
+    }
+};

Diff for: src/0988-Smallest-String-Starting-From-Leaf/0988.py

@@ -0,0 +1,14 @@
+# Definition for a binary tree node.
+class TreeNode:
+    def __init__(self, x):
+        self.val = x
+        self.left = None
+        self.right = None
+
+class Solution:
+    def smallestFromLeaf(self, root: 'TreeNode',path="") -> 'str':
+        if not root:
+            return "~"
+        s = chr(root.val + 97)
+        return s if root.left == root.right else min(self.smallestFromLeaf(root.left)\
+                                                     + s, self.smallestFromLeaf(root.right) + s)