Check If Queue Elements Are Pairwise Consecutive in Python

Suppose we have a queue full of numbers. We have to check whether the consecutive elements in the queue are pairwise consecutive or not.

So, if the input is like que = [3,4,6,7,8,9], then the output will be True.

To solve this, we will follow these steps −

• q := define a queue and insert all elements from given list into q
• temp := a new list
• while q is not empty, do
  • insert front element of queue into temp and delete front element from queue
• temp2 := a new list
• while temp is not empty, do
  • insert last element of temp into temp2
  • delete last element from temp
• result := True
• while size of temp2 > 1, do
  • x := last element of temp2
  • delete last element from temp2
  • y := last element of temp2
  • delete last element from temp2
  • if |x - y| is not 1, then
    • result := False
  • insert x and y into q
• if size of temp2 is 1, then
  • insert last element of temp2 into q
• return result

Example

Let us see the following implementation to get better understanding −

import queue
def solve(que):
   q = queue.Queue()
   for i in que:
      q.put(i)
   temp = []
   while q.qsize() != 0:
      temp.append(q.queue[0])
      q.get()
   temp2 = []
   while len(temp) != 0:
      temp2.append(temp[len(temp) - 1])
      temp.pop()
   result = bool(True)
   while len(temp2) > 1:
      x = temp2[len(temp2) - 1]
      temp2.pop()
      y = temp2[len(temp2) - 1]
      temp2.pop()
      if abs(x - y) != 1:
         result = False
      q.put(x)
      q.put(y)
   if len(temp2) == 1:
      q.put(temp2[len(temp2) - 1])
   return result
que = [3,4,6,7,8,9]
print(solve(que))

Input

[3,4,6,7,8,9]

Output

True