题干:
给定一个包含 m x n 个元素的矩阵(m 行, n 列),请按照顺时针螺旋顺序,返回矩阵中的所有元素。
示例 1:
输入: [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ] 输出: [1,2,3,6,9,8,7,4,5]
示例 2:
输入: [ [1, 2, 3, 4], [5, 6, 7, 8], [9,10,11,12] ] 输出: [1,2,3,4,8,12,11,10,9,5,6,7]
class Solution { public: vector<int> spiralOrder(vector<vector<int>>& matrix) { if (matrix.empty()) return vector<int>(); int m = matrix.size(),n = matrix[0].size(),i = 0,j = 0; vector<int>result; vector<vector<int>>visit(m,vector<int>(n));//申请一个数组,标记元素是否访问过 int count = m * n; while(count) { while(j < n && visit[i][j] == 0)//向右 { visit[i][j] = 1; result.push_back(matrix[i][j++]); count--; } i++,j--; while(i < m && visit[i][j] == 0)//向下 { visit[i][j] = 1; result.push_back((matrix[i++][j])); count--; } i--,j--; while(j >= 0 && visit[i][j] == 0)//向左 { visit[i][j] = 1; result.push_back(matrix[i][j--]); count--; } i--,j++; while(i >=0 && visit[i][j] == 0)//向上 { visit[i][j] = 1; result.push_back(matrix[i--][j]); count--; } i++,j++; n--,m--; } return result; } };