思路:模拟,初始化上下左右4个方向的边界,逐步收缩,注意要及时判断元素是否已经放满,否则会放入多余元素
class Solution {
public:
vector<int> spiralOrder(vector<vector<int>>& matrix) {
int row = matrix.size();
int col = matrix[0].size();
vector<int> ans;
int k = 1;
int left = 0;
int right = col-1;
int top = 0;
int bottom = row-1;
while(k <= row*col){
if(ans.size() == col * row) break;
for(int i = left;i<=right;++i,++k) ans.push_back(matrix[top][i]);
top++;
if(ans.size() == col * row) break;
for(int i = top;i<=bottom;++i,++k) ans.push_back(matrix[i][right]);
right--;
if(ans.size() == col * row) break;
for(int i = right;i>=left;--i,++k) ans.push_back(matrix[bottom][i]);
bottom--;
if(ans.size() == col * row) break;
for(int i = bottom;i>=top;--i,++k) ans.push_back(matrix[i][left]);
left++;
}
return ans;
}
};