How should I practice Unique Grid Paths?

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

Is Unique Grid Paths associated with Morgan Stanley?

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

Unique Grid Paths

Morgan Stanley● MediumFULLTIMEPHONE SCREEN

Problem statement

An m by n grid has no blocked cells. Start at the top-left cell and reach the bottom-right cell.

Each move goes one cell right or one cell down. Return the number of different paths. Two paths differ if their sequences of visited cells differ.

When the start and destination are the same cell, the path with no moves counts as one path. Return the exact count as a long.

Function

uniquePaths(m: int, n: int) → long

Examples

Example 1

m = 3n = 3return = 6

Each path has two right moves and two down moves. Choosing the two right-move positions among four positions gives 6 paths.

Example 2

m = 1n = 4return = 1

The only path makes three right moves.

Constraints

1 <= m, n <= 20.