Update README.md

Author: assassint2017

README.md

@@ -9,7 +9,7 @@
 1. [Two Sum](https://github.com/assassint2017/leetcode-algorithm/tree/master/Two%20Sum)
 2. [Add Two Numbers](https://github.com/assassint2017/leetcode-algorithm/tree/master/Add%20Two%20Numbers)
 3. [Longest Substring Without Repeating Characters](https://github.com/assassint2017/leetcode-algorithm/tree/master/Longest%20Substring%20Without%20Repeating%20Characters)  
-4. [Median of Two Sorted Arrays](https://github.com/assassint2017/leetcode-algorithm/tree/master/)  
+4. [Median of Two Sorted Arrays](https://github.com/assassint2017/leetcode-algorithm/tree/master/Median%20of%20Two%20Sorted%20Arrays)  
 5. [Longest Palindromic Substring](https://github.com/assassint2017/leetcode-algorithm/tree/master/)  
 6. [ZigZag Conversion](https://github.com/assassint2017/leetcode-algorithm/tree/master/)  
 7. [Reverse Integer](https://github.com/assassint2017/leetcode-algorithm/tree/master/)