Pour a List Into a Spiral

Medium

You are given the size of a table, rows × cols, and the head head of a singly linked list of non-negative integers. Fill the table with the list's values in order, moving in a spiral: start at the top-left corner going right, and turn clockwise at an edge or in front of an already filled cell. If the values run out before the cells do, every unfilled cell must hold -1. Return the resulting table.

Example 1

rows=3, cols=3, head=list_node([4, 0, 7, 2, 9, 5]) → [[4, 0, 7], [-1, -1, 2], [-1, 5, 9]]

The top row gets 4, 0, 7; the right column below it gets 2 and 9; then 5 lands in the middle of the bottom row. The other three cells stay -1.

Example 2

rows=2, cols=2, head=list_node([8, 3, 6, 1]) → [[8, 3], [1, 6]]

There are exactly as many values as cells: 8 and 3 on top, 6 in the bottom-right corner, 1 to its left.

Example 3

rows=1, cols=4, head=list_node([10]) → [[10, -1, -1, -1]]

Constraints

1 ≤ rows, cols
rows · cols ≤ 10⁵
The list has between 1 and rows · cols nodes
0 ≤ Node.val ≤ 1000

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Topics

Array Linked List Matrix Simulation

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Input

rows=3, cols=3, head=list_node([4, 0, 7, 2, 9, 5])

Expected

[[4, 0, 7], [-1, -1, 2], [-1, 5, 9]]

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