leetcode

0 class Solution {

1 public:

2 vector<vector<int>> spiralMatrixIII(const int rows, const int cols, int x, int y) {

3 static const int8_t offset_x[4] = {0, 1, 0, -1};

4 static const int8_t offset_y[4] = {1, 0, -1, 0};

5 vector<vector<int>> res;

6 res.reserve(rows * cols);

7 int dir = 0, cnt = 1, len = 1;

8

9 while (res.size() < rows * cols) {

10 for (int i = 0; i < len; i++) {

11 if (x >= 0 && x < rows && y >= 0 && y < cols) res.push_back({x, y});

12 x += offset_x[dir], y += offset_y[dir];

13 }

14 len += dir & 1;

15 dir = (dir + 1) & 0x3;

16 }

17

18 return res;

19 }

20 };