How should I practice Shortest Path Around Moving Parades?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Zip phone screen problems in FastPrep.

Is Shortest Path Around Moving Parades associated with Zip?

FastPrep tags this as a Zip phone screen coding practice problem when the problem catalog has that company and stage context.

Shortest Path Around Moving Parades

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Problem statement

A taxi moves on integer grid intersections. It begins at start = [x, y] at time 0 and must reach destination. Each second it moves exactly one cell east, north, south, or west. It may not wait.

Static barriers are blocked at every time. Each string in parades has the form "x,y,D", where D is E, N, S, or W. At time t, a parade head has advanced floor(t / 2) cells from [x, y] in direction D. The parade occupies its head and the entire semi-infinite line behind it:

An eastbound parade blocks its row at every x-coordinate at or west of its head.
A westbound parade blocks its row at every x-coordinate at or east of its head.
A northbound parade blocks its column at every y-coordinate at or south of its head.
A southbound parade blocks its column at every y-coordinate at or north of its head.

The taxi may not enter a cell blocked at its arrival time. Search only inside the inclusive rectangle bounds = [minX, maxX, minY, maxY].

Return a shortest valid direction string using E, N, S, and W. If several shortest strings exist, return the lexicographically smallest one. Return an empty string when no route exists.

Function

shortestParadePath(start: int[], destination: int[], barriers: int[][], parades: String[], bounds: int[]) → String

Examples

Example 1

start = [3,0]destination = [8,3]barriers = [[7,0],[7,1],[7,2],[7,3],[7,4],[8,2]]parades = []bounds = [-2,12,-2,8]return = "EEENNNNNEESS"

The route takes 12 steps, matching the minimum length reported for this barrier layout. It is the lexicographically smallest shortest route inside the rectangle.

Example 2

start = [3,0]destination = [3,4]barriers = []parades = ["2,3,E"]bounds = [-2,8,-2,8]return = "EENNNNWW"

The direct north route meets the growing eastbound parade on row 3. Moving east first crosses beyond its head before returning west above the parade.

Example 3

start = [0,0]destination = [0,2]barriers = [[0,1]]parades = []bounds = [0,0,0,2]return = ""

The only intermediate cell inside the rectangle is a barrier.

Constraints

start.length == destination.length == 2 and bounds.length == 4.
minX <= x <= maxX and minY <= y <= maxY for the start, destination, every barrier, and every parade head.
1 <= maxX - minX + 1 <= 40 and 1 <= maxY - minY + 1 <= 40.
0 <= barriers.length <= 1000 and 0 <= parades.length <= 20.
Static barriers are distinct, and every parade string is valid.