add cpp runner helper function

Author: tmp-coder

discrete-optimization/helper.py

@@ -0,0 +1,19 @@
+from subprocess import Popen, PIPE
+import os , re
+
+def cpp_runner(cpp_file_name,input_file_name):
+    """
+    this function for cpp programer
+    cpp_file_name: str , a cpp source code file name ends with .cpp
+    input_file_name: str, a input file name  
+    """
+    pat = re.compile(r'(.*).cpp')
+    m = pat.match(cpp_file_name)
+    # assert (m not None)
+    file_name = m.group(1)
+
+    os.system("g++ -std=c++11 -o3 "+cpp_file_name+" -o "+file_name)
+    process = Popen(['.\\'+file_name ,'<',input_file_name], stdout=PIPE)
+    (stdout, _) = process.communicate()
+
+    return stdout.strip().decode('utf-8')