题目描述
输入一个矩阵,按照从外向里以顺时针的顺序依次打印出每一个数字,例如,如果输入如下4 X 4矩阵: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 则依次打印出数字1,2,3,4,8,12,16,15,14,13,9,5,6,7,11,10.
tips: 使用递归,注意处理只有一行,和只有一列的情况。
class Solution {
public:
vector<int> printMatrix(vector<vector<int> > matrix) {
vector<int> now;
return recursivePrintMatrix(matrix,0,matrix.size()-1,0,matrix[0].size()-1,now);
}
vector<int> recursivePrintMatrix(vector<vector<int> >& matrix,int startX,int endX,int startY,int endY,vector<int> &resBefore) {
if(startX>endX||startY>endY) {
return resBefore;
}
vector<int> res=resBefore;
// 只有一行
if(startX==endX){
for (int i = startY; i <= endY; i++) {
res.push_back(matrix[startX][i]);
}
return res;
}
// 只有一列
if(startY==endY){
for (int i = startX; i <= endX; i++) {
res.push_back(matrix[i][endY]);
}
return res;
}
for (int i = startY; i < endY; i++)
{
res.push_back(matrix[startX][i]);
}
for (int i = startX; i < endX; i++)
{
res.push_back(matrix[i][endY]);
}
for (int i = endY; i >startY; i--)
{
res.push_back(matrix[endX][i]);
}
for (int i = endX; i >startX; i--)
{
res.push_back(matrix[i][startX]);
}
return recursivePrintMatrix(matrix,startX+1,endX-1,startY+1,endY-1,res);
}
};