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].
class Solution { public: vector<int> spiralOrder(vector<vector<int> > &matrix) { vector <int> result; int row=matrix.size()-1; if (row==0) return matrix[0]; else if (row==-1) return result; int col=matrix[0].size()-1; int layer=0; while(1){ for (int i=layer;i<=col;++i) result.push_back(matrix[layer][i]); for (int i=layer+1;i<=row;++i) result.push_back(matrix[i][col]); for (int i=col-1;i>=layer&&layer!=row;--i) result.push_back(matrix[row][i]); for (int i=row-1;i>=layer+1&&layer!=col;--i) result.push_back(matrix[i][layer]); ++layer; --col; --row; if (layer>col||layer>row) break; } return result; } };
原文：http://www.cnblogs.com/code-swan/p/4141242.html