CodingHardcod-g490

Subject Probability dpLevel Senior–Staff~30 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

In the gambler's ruin problem you start with `i` dollars and bet $1 per round; you win a round (gain $1) with probability p = p_num/p_den, else lose $1. You stop at $0 (ruin) or at $N (target). Return the probability of reaching $N before $0, rounded to 6 decimals. Handle both the fair (p=1/2) and biased cases.

Implement

gamblers_ruin_prob(N: int, i: int, p_num: int, p_den: int) → float

Examples

in[10,5,1,2]out0.5

What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

Learn the concepts

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.