在一个 m*n 的二维字符串数组中输出二叉树,并遵守以下规则:
示例 1:
输入:
1
/
2
输出:
[["", "1", ""],
["2", "", ""]]
示例 2:
输入:
1
/ \
2 3
\
4
输出:
[["", "", "", "1", "", "", ""],
["", "2", "", "", "", "3", ""],
["", "", "4", "", "", "", ""]]
示例 3:
输入:
1
/ \
2 5
/
3
/
4
输出:
[["", "", "", "", "", "", "", "1", "", "", "", "", "", "", ""]
["", "", "", "2", "", "", "", "", "", "", "", "5", "", "", ""]
["", "3", "", "", "", "", "", "", "", "", "", "", "", "", ""]
["4", "", "", "", "", "", "", "", "", "", "", "", "", "", ""]]
注意: 二叉树的高度在范围 [1, 10] 中。
来源:力扣(LeetCode) 链接:https://leetcode-cn.com/problems/print-binary-tree 著作权归领扣网络所有。商业转载请联系官方授权,非商业转载请注明出处。
height
width = 2^height - 1
class Solution {
public:
vector<vector<string>> printTree(TreeNode* root) {
int height = getHeight(root);//求高度
int width = (2<<(height-1))-1;//确定宽度
vector<vector<string>> ans(height,vector<string> (width,""));
dfs(ans,root,0,0,width-1);
return ans;
}
int getHeight(TreeNode* root)//递归求高度
{
if(root == NULL)
return 0;
return max(getHeight(root->left),getHeight(root->right))+1;
}
void dfs(vector<vector<string>> &ans, TreeNode* root, int f, int L, int R)
{
if(root == NULL)
return;
int mid = ((L+R)>>1);//区间中点
ans[f][mid] = to_string(root->val);//f深度
dfs(ans,root->left,f+1,L,mid-1);//递归填充左右侧
dfs(ans,root->right,f+1,mid+1,R);
}
};