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2326. Spiral Matrix IV

Difficulty Topics

Description

You are given two integers m and n, which represent the dimensions of a matrix.

You are also given the head of a linked list of integers.

Generate an m x n matrix that contains the integers in the linked list presented in spiral order (clockwise), starting from the top-left of the matrix. If there are remaining empty spaces, fill them with -1.

Return the generated matrix.

 

Example 1:

Input: m = 3, n = 5, head = [3,0,2,6,8,1,7,9,4,2,5,5,0]
Output: [[3,0,2,6,8],[5,0,-1,-1,1],[5,2,4,9,7]]
Explanation: The diagram above shows how the values are printed in the matrix.
Note that the remaining spaces in the matrix are filled with -1.

Example 2:

Input: m = 1, n = 4, head = [0,1,2]
Output: [[0,1,2,-1]]
Explanation: The diagram above shows how the values are printed from left to right in the matrix.
The last space in the matrix is set to -1.

 

Constraints:

  • 1 <= m, n <= 105
  • 1 <= m * n <= 105
  • The number of nodes in the list is in the range [1, m * n].
  • 0 <= Node.val <= 1000

Solution

spiral-matrix-iv.py
# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def spiralMatrix(self, rows: int, cols: int, head: Optional[ListNode]) -> List[List[int]]:
        matrix = [[-1] * cols for _ in range(rows)]

        i = j = 0
        d = [(0, 1), (1, 0), (0, - 1), (-1, 0)]
        dd = 0

        while head:
            val = head.val
            matrix[i][j] = val

            i += d[dd][0]
            j += d[dd][1]

            if i == rows or j == cols or i == -1 or j == -1 or matrix[i][j] != -1:
                i -= d[dd][0]
                j -= d[dd][1]

                dd = (dd + 1) % 4

                i += d[dd][0]
                j += d[dd][1]

            head = head.next

        return matrix