Task Tracker

Task Tracker

Medium Python OOP Basics 11 views
Explanation Complexity

Problem Statement

You will receive q commands: ADD name, DONE name, COUNT. Create TaskTracker class. COUNT prints how many tasks are pending.

Input Format

First line q. Next q lines commands.

Output Format

Outputs for COUNT.

Example

6
ADD study
ADD gym
COUNT
DONE study
COUNT
DONE gym
2
1

Constraints

q

Input / Output Format

Input Format
First line q. Next q lines commands.
Output Format
Outputs for COUNT.
Constraints
q

Examples

Input:
6 ADD study ADD gym COUNT DONE study COUNT DONE gym
Output:
2 1

Example Solution (Public)

Python 
import sys
lines=sys.stdin.read().splitlines()
if not lines: sys.exit(0)
q=int(lines[0].strip())
class TaskTracker:
  def __init__(self):
    self.pending=set()
  def add(self,name):
    self.pending.add(name)
  def done(self,name):
    if name in self.pending:
      self.pending.remove(name)
  def count(self):
    return len(self.pending)
t=TaskTracker()
out=[]
for i in range(1,1+q):
  parts=(lines[i] if i<len(lines) else '').split()
  if not parts: continue
  if parts[0]=='ADD':
    t.add(parts[1])
  elif parts[0]=='DONE':
    t.done(parts[1])
  else:
    out.append(str(t.count()))
print('\
'.join(out))

Official Solution Code

import sys
lines=sys.stdin.read().splitlines()
if not lines: sys.exit(0)
q=int(lines[0].strip())
class TaskTracker:
  def __init__(self):
    self.pending=set()
  def add(self,name):
    self.pending.add(name)
  def done(self,name):
    if name in self.pending:
      self.pending.remove(name)
  def count(self):
    return len(self.pending)
t=TaskTracker()
out=[]
for i in range(1,1+q):
  parts=(lines[i] if i<len(lines) else '').split()
  if not parts: continue
  if parts[0]=='ADD':
    t.add(parts[1])
  elif parts[0]=='DONE':
    t.done(parts[1])
  else:
    out.append(str(t.count()))
print('\
'.join(out))
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Output

                                        

                                    

                                    

                                        

                                                                                    
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