update

solutions/system_design/pastebin/README.md

@@ -130,7 +130,7 @@ To generate the unique url, we could:
     * Base 64 is another popular encoding but provides issues for urls because of the additional `+` and `/` characters
     * The following [Base 62 pseudocode](http://stackoverflow.com/questions/742013/how-to-code-a-url-shortener) runs in O(k) time where k is the number of digits = 7:
 
-```
+```python
 def base_encode(num, base=62):
     digits = []
     while num > 0
@@ -142,13 +142,13 @@ def base_encode(num, base=62):
 
 * Take the first 7 characters of the output, which results in 62^7 possible values and should be sufficient to handle our constraint of 360 million shortlinks in 3 years:
 
-```
+```python
 url = base_encode(md5(ip_address+timestamp))[:URL_LENGTH]
 ```
 
 We'll use a public [**REST API**](https://github.com/donnemartin/system-design-primer#representational-state-transfer-rest):
 
-```shell
+```
 $ curl -X POST --data '{ "expiration_length_in_minutes": "60", \
     "paste_contents": "Hello World!" }' https://pastebin.com/api/v1/paste
 ```
@@ -182,8 +182,8 @@ Response:
 
 ```
 {
-    "paste_contents": "Hello World",
-    "created_at": "YYYY-MM-DD HH:MM:SS",
+    "paste_contents": "Hello World"
+    "created_at": "YYYY-MM-DD HH:MM:SS"
     "expiration_length_in_minutes": "60"
 }
 ```
@@ -194,7 +194,7 @@ Since realtime analytics are not a requirement, we could simply **MapReduce** th
 
 **Clarify with your interviewer how much code you are expected to write**.
 
-```
+```python
 class HitCounts(MRJob):
 
     def extract_url(self, line):