Philly Daily Programmer: 5-8-2016

HmSh-10.py

'''
Given a sorted list of distinct integers, write a function that returns whether there are two integers in the list that add up to 0. For example, you would return true if both -14435 and 14435 are in the list, because -14435 + 14435 = 0. Also return true if 0 appears in the list.

[1, 2, 3] -> false
[-5, -3, -1, 2, 4, 6] -> false
https://repl.it/HmSh/10 
'''


test1 = [] #False
test2 = [0] #True
test3 = [-1, 1] #True
test4 = [1, 2] #False
test5 = [-2, 1, 2] #True
test6 = [-5, 0, 4] #True
test7 = [1, 2, 3] #False
test8 = [-5, -3, -1, 2, 4, 6] #False

alltests = [test1, test2, test3, test4, test5, test6, test7, test8]

def runTest(test):
  front = 0
  back = len(test)-1
  if len(test)==0: return False
  elif len(test)==1 and test[front]==0: return True
  else:
    while(front != back):
      if test[front] == 0 or test[back] == 0: return True
      elif test[front] > 0 or test[back] < 0: return False
      elif test[front]+test[back] == 0: return True
      elif abs(test[front]) >= abs(test[back]): front+=1 
      else: back-=1
  return False

for t in alltests:
  print("Running test %s: %s" % (str(t), str(runTest(t))))