feat: Add function to get info for a problem

Author: Mukundan314

codeforces/__init__.py

@@ -1,2 +1,3 @@
 from . import error
 from . import api
+from . import problem

codeforces/problem.py

@@ -0,0 +1,55 @@
+import os
+import urllib.request
+import urllib.error
+from bs4 import BeautifulSoup
+
+__all__ = ['get_info']
+
+CODEFORCES_URL = "https://codeforces.com"
+
+
+def get_info(contest_id, index, lang='en'):
+    """
+    Get info for a contest problem.
+
+    Parameters
+    ----------
+    contest_id: int
+        Id of the contest. It is not the round number. It can be seen in
+        contest URL. For example: /contest/**566**/status
+    index: str
+        Usually a letter of a letter, followed by a digit, that
+        represent a problem index in a contest. It can be seen in
+        problem URL. For example: /contest/566/**A**
+
+    Returns
+    -------
+    title: str
+        Title of the problem.
+    time_limit: str
+        Time limit specification for the problem.
+    memory_limit: str
+        Memory limit specification for the problem.
+    sample_tests: zip
+        Sample tests given for the problem.
+    """
+
+    problem_url = os.path.join(
+        CODEFORCES_URL,
+        "contest/%d/problem/%s?lang=%s" % (contest_id, index, lang)
+    )
+
+    with urllib.request.urlopen(problem_url) as res:
+        soup = BeautifulSoup(res.read(), 'html.parser')
+
+    title = soup.find_all("div", class_="title")[0].text
+
+    time_limit = soup.find_all("div", class_="time-limit")[0].text[19:]
+    memory_limit = soup.find_all("div", class_="memory-limit")[0].text[21:]
+
+    i = [i.pre.string[1:] for i in soup.find_all("div", class_="input")]
+    o = [i.pre.string[1:] for i in soup.find_all("div", class_="output")]
+
+    sample_tests = zip(i, o)
+
+    return (title, time_limit, memory_limit, sample_tests)