So fun! It connects algorithm(regex) with real world usages!
So basically speaking, C:pointer syntax, #include\scanf\typedef; Java: import\public class syntax\try-catch syntax; Python: def syntax\special print syntax.
And BTW, if you are working on regex problems with Python, this is god-sent: http://pythex.org/
import re import io import sys input_stream = io.TextIOWrapper(sys.stdin.buffer, encoding='utf-8') s = input_stream.readlines() s = "\n".join(s) pc = '([^/]\*[a-zA-Z]+\w*|typedef|#include|scanf)' pj = '(import\s+|public\s+class|catch\s*[(].*?[)]|System\.)' pp = '(print\s+[\w\"]+|[(][[][\"\s\w,]+[]][)]|def\s+[\w]+[(])' mc = re.findall(pc, s) mj = re.findall(pj, s) mp = re.findall(pp, s) bc = len(mc) > 0 bj = len(mj) > 0 bp = len(mp) > 0 if bc: print ("C") if bj: print ("Java") if bp: print ("Python")