LeetCode-in-Java
2326. Spiral Matrix IV
Medium
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 <= 1051 <= m * n <= 105- The number of nodes in the list is in the range
[1, m * n]. 0 <= Node.val <= 1000
Solution
import com_github_leetcode.ListNode;
/*
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode() {}
* ListNode(int val) { this.val = val; }
* ListNode(int val, ListNode next) { this.val = val; this.next = next; }
* }
*/
public class Solution {
private enum Direction {
RIGHT,
DOWN,
LEFT,
UP
}
public int[][] spiralMatrix(int m, int n, ListNode head) {
int[][] arr = new int[m][n];
int i = 0;
int j = -1;
Direction direction = Direction.RIGHT;
// Boundaries
// ++ after Left to right Horizontal traversed
int a = 0;
// -- after Down to Up vertical traversed
int b = n - 1;
// -- after Right to Left horizontal teversed
int c = m - 1;
// ++ after Down to Up vertical traversed
int d = 0;
for (int k = 0; k < m * n; ++k) {
int val = -1;
if (head != null) {
val = head.val;
head = head.next;
}
switch (direction) {
case RIGHT:
++j;
if (j == b) {
direction = Direction.DOWN;
++a;
}
break;
case DOWN:
++i;
if (i == c) {
direction = Direction.LEFT;
}
break;
case LEFT:
--j;
if (j == d) {
--c;
direction = Direction.UP;
}
break;
case UP:
default:
--i;
if (i == a) {
--b;
++d;
direction = Direction.RIGHT;
}
break;
}
arr[i][j] = val;
}
return arr;
}
}