SpiralMatrix.cpp

#include <iostream>
#include <vector>
using namespace std;

vector<int> spiralOrder(vector<vector<int>> &matrix)
{
    int m = matrix.size(), n = matrix[0].size();
    int srow = 0, scol = 0, erow = m - 1, ecol = n - 1;
    vector<int> ans;

    while (srow <= erow && scol <= ecol)
    {
        // top
        for (int j = scol; j <= ecol; j++)
        {
            ans.push_back(matrix[srow][j]);
        }

        // right
        for (int i = srow + 1; i <= erow; i++)
        {
            ans.push_back(matrix[i][ecol]);
        }

        // bottom
        for (int j = ecol - 1; j >= scol; j--)
        {
            if (srow == erow)
            {
                break;
            }
            ans.push_back(matrix[erow][j]);
        }

        // left
        for (int i = erow - 1; i >= srow + 1; i--)
        {
            if (scol == ecol)
            {
                break;
            }
            ans.push_back(matrix[i][scol]);
        }

        srow++;
        erow--;
        scol++;
        ecol--;
    }

    return ans;
}

int main()
{
    vector<vector<int>> matrix = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16}};

    vector<int> result = spiralOrder(matrix);

    for (int num : result)
    {
        cout << num << " ";
    }
    cout << endl;

    return 0;
}