GFG PTOD | 20 DEC | spirally-traversing-a-matrix

vector<int> spirallyTraverse(vector<vector<int> > &mat) {
        // code here
        int row = mat.size(), col = mat[0].size();
        int left = 0, top = 0, right = col-1, bottom = row-1, d=0;
        vector<int> ans;
        
        while(left <= right && top <= bottom) {
            switch(d) {
                case 0:
                    for(int i = left; i<=right; i++)
                        ans.push_back(mat[top][i]);
                    top++;
                    break;
                case 1:
                    for(int i = top; i<=bottom; i++) 
                        ans.push_back(mat[i][right]);
                    right--;
                    break;
                case 2:
                    for(int i=right; i>=left; i--)
                        ans.push_back(mat[bottom][i]);
                    bottom--;
                    break;
                case 3:
                    for(int i=bottom; i>=top; i--)
                        ans.push_back(mat[i][left]);
                    left++;
                    break;
            }
            if(d==3) d=0;
            else d++;
        }
        return ans;
    }