Find Heavier Ball | Dataford Interview Questions

Find the heavier ball from 8 balls.

Assume exactly one ball is heavier than the other seven, and a balance scale is available. Use at most two weighings: first compare balls 0, 1, 2 against balls 3, 4, 5; then compare either balls 0 and 1 or balls 6 and 7, depending on the first result. Each weighing result is 1 if the left side is heavier, -1 if the right side is heavier, and 0 if they balance. Implement find_heavier_ball(first_result, second_result) to return the heavier ball's index from 0 through 7.

Constraints

There are exactly 8 balls indexed from 0 through 7.
Exactly one ball is heavier than the other seven.
first_result and second_result are each one of -1, 0, or 1.
The results are valid outcomes of the described weighing strategy.

Function Signature

def find_heavier_ball(first_result, second_result):

Whenever you're ready, walk me through your approach or go straight to the code. The requirements are in the Question tab.

Problem

Find the heavier ball from 8 balls.

Constraints

There are exactly 8 balls indexed from 0 through 7.
Exactly one ball is heavier than the other seven.
first_result and second_result are each one of -1, 0, or 1.
The results are valid outcomes of the described weighing strategy.

Function Signature

def find_heavier_ball(first_result, second_result):

Whenever you're ready, walk me through your approach or go straight to the code. The requirements are in the Question tab.