How should I practice Longest Consecutive Decreasing Grid Path?

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

Is Longest Consecutive Decreasing Grid Path associated with Google?

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

Longest Consecutive Decreasing Grid Path

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Problem statement

Given a nonempty integer matrix grid, return the maximum number of cells in a path whose values decrease consecutively.

From a cell with value x, the next cell must share an edge with it and have value exactly x - 1. A path may start at any cell and move up, down, left, or right.

Function

longestConsecutiveDecreasingPath(grid: int[][]) → int

Examples

Example 1

grid = [[5,4,3],[6,1,2],[7,0,-1]]return = 9

The path follows 7,6,5,4,3,2,1,0,-1.

Example 2

grid = [[3,2],[2,1]]return = 3

Either cell containing 2 can connect 3 to 1.

Example 3

grid = [[4,1],[2,0]]return = 2

The longest path is 1,0; diagonal cells are not adjacent.

Constraints

1 <= grid.length, grid[0].length <= 200.
Every row has the same length.
Every value is a signed 32-bit integer.