题目连接
https://leetcode.com/problems/spiral-matrix/
Spiral Matrix
Description
Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.
For example,
Given the following matrix:
[
[ 1, 2, 3 ],
[ 4, 5, 6 ],
[ 7, 8, 9 ]
]
You should return [1,2,3,6,9,8,7,4,5].
蛇形填数。。
class Solution {
public:
vector<int> spiralOrder(vector<vector<int>>& matrix) {
ans.clear();
if (matrix.empty() || matrix[0].empty()) return ans;
n = matrix.size(), m = matrix[0].size();
int x = 0, y = 0, tot = 1;
vector<vector<int>> vis(n, vector<int>(m));
ans.push_back(matrix[x][y]), vis[x][y] = true;
while (tot < n * m) {
while (y + 1 < m && !vis[x][y + 1]) ans.push_back(matrix[x][++y]), vis[x][y] = true, tot++;
while (x + 1 < n && !vis[x + 1][y]) ans.push_back(matrix[++x][y]), vis[x][y] = true, tot++;
while (y - 1 >= 0 && !vis[x][y - 1]) ans.push_back(matrix[x][--y]), vis[x][y] = true, tot++;
while (x - 1 >= 0 && !vis[x - 1][y]) ans.push_back(matrix[--x][y]), vis[x][y] = true, tot++;
}
return ans;
}
private:
int n, m;
vector<int> ans;
};