How should I practice Maximum Riders in Car?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Uber online assessment problems in FastPrep.

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Problem · Array

Maximum Riders in Car

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Problem statement

There are n riders and one car with infinite capacity. Each rider i is comfortable riding in the car only if the number of other riders also in the car is between comfort[i][0] and comfort[i][1] (inclusive). If this condition is not met, the rider will not enter the car.

All riders decide simultaneously — a valid group is a subset of riders where every rider in the group is comfortable with the group size minus one.

Return the maximum number of riders that can be in the car at the same time.

Function

maxRiders(comfort: int[][]) → int

Examples

Example 1

comfort = [[1, 3], [2, 4], [0, 2], [1, 3]]return = 3

With k=3 riders, each needs to be comfortable with 2 others. Riders 0 (1–3), 1 (2–4), and 2 (0–2) all include 2 in their range → valid group of 3.
With k=4, each would need 3 others. Only riders 0, 1, and 3 cover 3 — only 3 riders qualify, not 4.

Example 2

comfort = [[0, 2], [0, 2], [0, 2]]return = 3

With all 3 riders, each is comfortable with 2 others (2 ∈ [0, 2]). All 3 can ride together.

Example 3

comfort = [[2, 3], [2, 3]]return = 0

k=1 requires 0 others; k=2 requires 1 other. Neither 0 nor 1 falls in [2, 3] for any rider, so no valid group exists.

Example 4

comfort = [[0, 0]]return = 1

The single rider is comfortable with 0 others. They ride alone.

Constraints

1 ≤ n ≤ 10⁵
0 ≤ comfort[i][0] ≤ comfort[i][1] ≤ n