Code Room
CodingHardcod-g763
Subject GreedyLevel Senior–Staff~35 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

A garden runs along a line from point 0 to point n. There are n+1 taps at integer points 0..n; tap i has range ranges[i], meaning when open it waters the closed interval [i - ranges[i], i + ranges[i]]. Return the minimum number of taps to open so the entire garden [0, n] is watered, or -1 if it is impossible. Constraints: 1 <= n <= 10^4, 0 <= ranges[i] <= 100, len(ranges) == n + 1.

Implement
min_taps(n: int, ranges: list[int]) → int
Examples
in[5,[3,4,1,1,0,0]]out1
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.

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.