先求出h,然后计算w
每次root放中间,然后递归计算左右子树
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C++ 代码
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
vector<vector<string>> printTree(TreeNode* root) {
int h = dfs(root)-1;
int w = pow(2, h+1) - 1;
// printf("%d,%d\n", h,w);
vector<vector<string>> res = vector<vector<string>>(h+1, vector<string>(w, ""));
print(root, 0, 0, w-1, res);
return res;
}
int dfs(TreeNode* root){
if(!root)return 0;
return 1 + max(dfs(root->left), dfs(root->right));
}
void print(TreeNode* root, int h, int l, int r, vector<vector<string>>& res) {
if(!root)return;
int mid = (l+r)>>1;
res[h][mid] = to_string(root->val);
print(root->left, h+1, l, mid-1, res);
print(root->right, h+1, mid+1, r, res);
}
};