54.螺旋矩阵-1.cpp

/*
 * @lc app=leetcode.cn id=54 lang=cpp
 *
 * [54] 螺旋矩阵
 */
// 官方方法 1
// @lc code=start
class Solution {
  private:
    static constexpr int directions[4][2] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};

  public:
    vector<int> spiralOrder(vector<vector<int>> &matrix) {
        if (matrix.size() == 0 || matrix[0].size() == 0) {
            return {};
        }

        int rows = matrix.size(), columns = matrix[0].size();
        vector<vector<bool>> visited(rows, vector<bool>(columns));
        int total = rows * columns;
        vector<int> order(total);

        int row = 0, column = 0;
        int directionIndex = 0;
        for (int i = 0; i < total; i++) {
            order[i] = matrix[row][column];
            visited[row][column] = true;
            int nextRow = row + directions[directionIndex][0], nextColumn = column + directions[directionIndex][1];
            if (nextRow < 0 || nextRow >= rows || nextColumn < 0 || nextColumn >= columns || visited[nextRow][nextColumn]) {
                directionIndex = (directionIndex + 1) % 4;
            }
            row += directions[directionIndex][0];
            column += directions[directionIndex][1];
        }
        return order;
    }
};
// @lc code=end