Ball Relay Simulation | Dataford Interview Questions

An array of numbers: the ith person throws the ball to a[i] every second. At time t, where will the ball be?

Asked in the Tech interview round 1 stage.

Write a function that returns the index of the person holding the ball after exactly t seconds, starting from person start. The ball moves once per second, and at each second the current holder throws it to a[current].

Function

def ball_position(a, start, t):

Input

a: list of integers, where a[i] is the next person index for person i
start: integer, the starting holder index
t: non-negative integer, number of seconds

Output

Return the index of the person holding the ball after t throws.

Constraints

1 <= len(a) <= 10^5
0 <= a[i] < len(a)
0 <= start < len(a)
0 <= t <= 10^18

Function Signature

def ball_position(a, start, t):

Your question is Ball Relay Simulation. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem