2326. Spiral Matrix IV

/**
 * 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 {
public:
    vector<vector<int>> spiralMatrix(int n, int m, ListNode* head) {
        vector<vector<int>> ans(n,vector<int> (m,-1));
        int left=0;
        int right=m-1;
        int top=0;
        int bottom=n-1;
        ListNode* temp=head;
        while (top<=bottom && left<=right){
            for(int i=left;i<=right && temp;i++){
                ans[top][i]=temp->val;
                temp=temp->next;
            }
            top++;
            for(int i=top;i<=bottom && temp;i++){
                ans[i][right]=temp->val;
                temp=temp->next;
            }
            right--;
            if(top<=bottom){
                for(int i=right;i>=left && temp;i--){
                    ans[bottom][i]=temp->val;
                    temp=temp->next;
                }
                bottom--;
            }
            if(left<=right){
                for(int i=bottom;i>=top && temp;i--){
                    ans[i][left]=temp->val;
                    temp=temp->next;
                }
                left++;
            }
        }
        return ans;
    }
};