SpiralMatrix.cpp

class Solution {
public:
    vector<int> spiralOrder(vector<vector<int>>& matrix) {
        if(!matrix.size())
            return {};
        int i, dir = 0, T = 0, B = matrix.size() - 1, L = 0, R = matrix[0].size() - 1;
        vector<int> ans;
        
        while(T <= B && L <= R)
        {
            if(dir == 0)
            {
                for(i = L; i <= R; i++)
                    ans.push_back(matrix[T][i]);
        
                T++;
            }
            
            else if(dir == 1)
            {
                for(i = T; i <= B; i++)
                    ans.push_back(matrix[i][R]);
                    
                R--;
            }
            
            else if(dir == 2)
            {
                for(i = R; i >= L; i--)
                    ans.push_back(matrix[B][i]);
                    
                B--;
            }
            
            else 
            {
                for(i = B; i >= T; i--)
                    ans.push_back(matrix[i][L]);
                    
                L++;
            }
                      
            dir = (dir + 1) % 4;
        }
        return ans;
    }
};