2326. Spiral Matrix IV

 C++

class Solution {
public:
    vector<vector<int>> spiralMatrix(int m, int n, ListNode* head) {
        vector<vector<int>> ans(m, vector<int>(n, -1));
        int i = 0, j = 0, p = 0;
        vector<vector<int>> dirs = { {0, 1}, {1, 0}, {0, -1}, {-1, 0} };
        while (1) {
            ans[i][j] = head->val;
            head = head->next;
            if (!head) break;
            while (1) {
                int x = i + dirs[p][0], y = j + dirs[p][1];
                if (x < 0 || y < 0 || x >= m || y >= n || ans[x][y] >= 0)
                    p = (p + 1) % 4;
                else {
                    i = x, j = y;
                    break;
                }
            }
        }
        return ans;
    }
};

JAVA

class Solution {
    public int[][] spiralMatrix(int m, int n, ListNode head) {
        int[][] ans = new int[m][n];
        for (int[] row : ans) {
            Arrays.fill(row, -1);
        }
        int i = 0, j = 0, p = 0;
        int[][] dirs = { {0, 1}, {1, 0}, {0, -1}, {-1, 0} };
        while (true) {
            ans[i][j] = head.val;
            head = head.next;
            if (head == null) {
                break;
            }
            while (true) {
                int x = i + dirs[p][0], y = j + dirs[p][1];
                if (x < 0 || y < 0 || x >= m || y >= n || ans[x][y] >= 0) {
                    p = (p + 1) % 4;
                } else {
                    i = x;
                    j = y;
                    break;
                }
            }
        }
        return ans;
    }
}