Google Interview Question
Applications DevelopersCountry: United States
On the basis of 1 and 3 data we can put a default floor(the floor to which lift returns automatically when no service requests are pending) for that specific time... For instance having the default floor of all the lift to the ground floor (concourse) will be helpful in reducing the average wait time of the employees. Ans similarly in the evening the topmost floor can be set as default floor.
Just guessing:
Maybe track how many floors each elevator is serving. That could be slowing down the process.
Algorithm that the elevator is using to figure in what order various floors are to be served, provided many people are requesting the elevator at once.
May be we can work on the open and close mechanism of the door. Some old elevators do take a lot of time opening and closing the doors.
Reason for being slow might be: 1) There are people getting in and out on every floor
2)Lift equipment might be in repair
Corresponding Solutions:
1)Make the lift stop only at alternate floors so that number of stoppings decrease and people have to take at most one floor stairs which is relatively better compared to waiting.
2)May be the motor could be repaired.
Others:
Have a web portal or mobile app which tells when the lift stops at his floor when he gives from and to details so that he can reduce his time waiting
Some of the matrices i can think of
1.Determine the capacity of motor first..
2. How many people at once are currently travelling in lift.
Say if employees want it to reach the top-most floor after x seconds, then based on above two data we can set a limit on the number of people that should go inside the lift at once/per floor. Maybe because more no of people are travelling at once its speed is less.
3.Average age of employees.. Say if most people are young encourage them to use stairs rather than lift.
4.Time duration at which lift is mostly used...so at time of rush we can allow more people to travel but with info that lift would take more time..so either wait outside the lift or inside the lift :)
Matrices gathered can be:
- Subhajit June 15, 20131> Average number of employes using the lift during the peak times(morning time and evening time)
2> Age distribution of the employes using the lift at peak times
3> Average number of times the lift changes direction(moving up to moving down, moving down to moving up)
4>Floors where the crowd is more
5>Lift door open and closing time
By knowing the average number of people using lift at peak times, may be its worth suggesting to management to get another lift.
With age distribution, we can suggest young employees to use stairs if possible.
The number of times the lift changes the direction, may be useful in improving the algorithm used by the lift for servicing requests.
For crowded floors, may be there can be separate lift movements at specific times of the day serving these floors.
Reduction in the door opening and closing timing may have some improvement.