Snail Well Climb Time | Dataford Interview Questions

Tavant is modeling incremental progress in a delivery estimate. A snail starts at the bottom of a well and repeats this cycle each day: it climbs climb feet, then slips slip feet, unless it reaches the top during that day's climb.

Return the number of days required to reach the top of a well with height height. If the snail can never reach the top, return -1.

Formal Specification

Implement days_to_top(height, climb, slip), where all three inputs are positive integers. Return an integer representing the first day on which the snail reaches or exceeds the top. The slip occurs only after an unsuccessful climb.

Use an arithmetic solution rather than simulating every day, because height may be very large.

Constraints

1 <= height, climb, slip <= 10^18
Return -1 if the snail can never reach the top.
The snail starts at height 0.
Slipping occurs only after an unsuccessful climb.

Function Signature

def days_to_top(height, climb, slip):

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