PlusMinus

gistfile1.txt

# Echo client program
import socket
import math
import numexpr

x = ['+','-','/', '*']

e = 0.00001


def evaluate(stringexpr, listexpr=0, n=0, f_operation='+'):
    if stringexpr:
        listexpr = ([c for c in stringexpr+')' ])
        listexpr.reverse()

    
    while f_operation != ')':
        m_next = listexpr.pop()
        if m_next == '(':
            m_next = evaluate(None, listexpr)

        else:
            while listexpr[-1] not in '+-*/)':
                m_next += listexpr.pop()

        m = float(m_next)
        if f_operation == '+':
          n = n+m
        elif f_operation == '-':
          n = n-m
        elif f_operation == '*':
          n = n*m
        else:
          n= n/(m or 1)

        f_operation = listexpr.pop()

    return n

def f(q, a, p, n, openb, b):
  if p == n:
    qq = q + openb * ')'
    
    
    ans = evaluate(qq)
    if math.fabs(ans - b) < e:
      return qq
          
    qq = '-' + qq
    ans = evaluate(qq)
    if math.fabs(ans - b) < e:
      return qq
    return None
    
  if p == 0:
    for k in range(n-p):
        qq = '(' * k + a[p]
        ans = f(q + qq, a, p+1, n, openb + k, b)
        if ans is not None:
          return ans
  elif p == n - 1:
    for i in range(openb+1):
      for j in x:
          qq = ')' * i + j + a[p]
          ans = f(q + qq, a, p+1, n, openb - i, b)
          if ans is not None:
            return ans
    
  else:
    for i in range(openb+1):
      for j in x:
        for k in range(n-p):
          qq = ')' * i + j  +  '(' * k + a[p]
          ans = f(q + qq, a, p+1, n, openb - i + k, b)
          if ans is not None:
            return ans
  

def solve(s):
  print(s)
  a = s.split()
  b = float(a[-1])
  a = a[:-1]
  
  ans = f('', a,0, len(a), 0, b)
  print(ans)
  return ans + '\n'
  


HOST = 'ppc-01.v7frkwrfyhsjtbpfcppnu.ctfz.one'    # The remote host
PORT = 2445              # The same port as used by the server
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.connect((HOST, PORT))
    while True:
      data = s.recv(1024).decode('utf8')
      data = data.split('\n')
      print('Data: ', data)
      if data[-2] == 'Success':
        continue 
      answer = solve(data[-2])
      s.sendall(answer.encode())