Rate Limiter System

Part 1 — Binary Search: Find the minimum tier for a given request volume.

tiers = [
    {"tier": "free",       "max_requests": 100},
    {"tier": "basic",      "max_requests": 1000},
    {"tier": "pro",        "max_requests": 10000},
    {"tier": "enterprise", "max_requests": 100000},
]
find_tier(5000, tiers) → "pro"

Part 2 — Recursion: Calculate total leaf capacity in an infrastructure tree.

total_capacity(node) → sum of all leaf max_capacity values

Part 3 — Graph: Calculate total cost of calling an endpoint (including all dependencies).

calculate_cost("/user/profile", graph) → 4  (1 + deps)