多数次过。很奇怪dfs函数声明的时候形参里dir[][]不能用，必须为dir[4][2].
1 class Solution { 2 public: 3 bool out(int x, int y, int m, int n) { 4 if (x >= m || x < 0 || y >= n || y < 0) return true; 5 return false; 6 } 7 void dfs(int x, int y, int dir[4][2], int dep, int m, int n, vector<int> &ret, 8 int direct, vector<vector<bool>> &visit, vector<vector<int>> matrix) { 9 if (dep == m*n) return; 10 visit[x][y] = true; 11 ret.push_back(matrix[x][y]); 12 if (out(x+dir[direct][0], y+dir[direct][1], m, n) || visit[x+dir[direct][0]][y+dir[direct][1]]) 13 direct = (direct+1) % 4; 14 dfs(x+dir[direct][0], y+dir[direct][1], dir, dep+1, m, n, ret, direct, visit, matrix); 15 } 16 vector<int> spiralOrder(vector<vector<int> > &matrix) { 17 // Start typing your C/C++ solution below 18 // DO NOT write int main() function 19 vector<int> ret; 20 if (!matrix.size()) return ret; 21 int m = matrix.size(); 22 int n = matrix[0].size(); 23 int dir[4][2] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}}; 24 vector<vector<bool>> visit(m, vector<bool>(n, false)); 25 dfs(0, 0, dir, 0, m, n, ret, 0, visit, matrix); 26 return ret; 27 } 28 };
后来写了个不用递归的，这个复杂度会低
1 class Solution { 2 public: 3 bool check(int x, int y, int dir[4][2], int curdir, int m, int n, vector<vector<bool> > &visit) { 4 int xx = x + dir[curdir][0]; 5 int yy = y + dir[curdir][1]; 6 if (xx >= 0 && xx < m && yy >= 0 && yy < n && !visit[xx][yy]) return true; 7 else return false; 8 } 9 vector<int> spiralOrder(vector<vector<int> > &matrix) { 10 // Start typing your C/C++ solution below 11 // DO NOT write int main() function 12 vector<int> ret; 13 if (!matrix.size() || !matrix[0].size()) return ret; 14 int m = matrix.size(); 15 int n = matrix[0].size(); 16 vector<vector<bool> > visit(m, vector<bool>(n)); 17 int dir[4][2] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}}; 18 int dep, x, y, curdir; 19 curdir = x = y = dep = 0; 20 ret.push_back(matrix[0][0]); 21 visit[0][0] = true; 22 dep++; 23 while (dep < m*n) { 24 while (!check(x, y, dir, curdir, m, n, visit)) curdir = (curdir+1)%4; 25 x += dir[curdir][0]; 26 y += dir[curdir][1]; 27 visit[x][y] = true; 28 ret.push_back(matrix[x][y]); 29 dep++; 30 } 31 return ret; 32 } 33 };
C#
1 public class Solution { 2 public List<int> SpiralOrder(int[,] matrix) { 3 List<int> ans = new List<int>(); 4 int m = matrix.GetLength(0); 5 int n = matrix.GetLength(1); 6 if (m == 0 || n == 0) return ans; 7 bool[,] visit = new bool[m, n]; 8 int[,] dir = new int[4, 2] {{0, 1}, {1, 0}, {0, -1}, {-1, 0}}; 9 int dep = 0, x = 0, y = 0, curdir = 0; 10 ans.Add(matrix[0, 0]); 11 visit[0, 0] = true; 12 dep++; 13 while (dep < m * n) { 14 while (!check(x, y, dir, curdir, m, n, visit)) curdir = (curdir + 1) % 4; 15 x += dir[curdir, 0]; 16 y += dir[curdir, 1]; 17 visit[x, y] = true; 18 ans.Add(matrix[x, y]); 19 dep++; 20 } 21 return ans; 22 } 23 public bool check(int x, int y, int[,] dir, int curdir, int m, int n, bool[,] visit) { 24 int xx = x + dir[curdir, 0]; 25 int yy = y + dir[curdir, 1]; 26 if (xx >= 0 && xx < m && yy >= 0 && yy < n && !visit[xx, yy]) return true; 27 else return false; 28 } 29 }