Today I have done leetcode's September LeetCoding Challenge with cpp.

September LeetCoding Challenge 9

Description

Spiral Matrix IV

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

happy birthday to myself~

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
  const int MOVES[4][2] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
public:
  vector<vector<int>> spiralMatrix(int m, int n, ListNode* head) {
    vector<vector<int>> answer(m, vector<int>(n, -1));
    int x = 0;
    int y = -1;
    while(head) {
      int move = 0;
      for(int i = 0; i < n && head; ++i) {
        x += MOVES[move][0];
        y += MOVES[move][1];
        answer[x][y] = head->val;
        head = head->next;
      }
      move += 1;
      for(int i = 0; i < m - 1 && head; ++i) {
        x += MOVES[move][0];
        y += MOVES[move][1];
        answer[x][y] = head->val;
        head = head->next;
      }
      move += 1;
      for(int i = 0; i < n - 1 && head; ++i) {
        x += MOVES[move][0];
        y += MOVES[move][1];
        answer[x][y] = head->val;
        head = head->next;
      }
      move += 1;
      for(int i = 0; i < m - 2 && head; ++i) {
        x += MOVES[move][0];
        y += MOVES[move][1];
        answer[x][y] = head->val;
        head = head->next;
      }
      n -= 2;
      m -= 2;
    }
    return answer;
  }
};