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Java Solution for LeetCode algorithm problems, continually updating
package g0601_0700.s0623_add_one_row_to_tree;
// #Medium #Depth_First_Search #Breadth_First_Search #Tree #Binary_Tree
// #2022_03_21_Time_0_ms_(100.00%)_Space_45.6_MB_(29.97%)
import com_github_leetcode.TreeNode;
/*
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode() {}
* TreeNode(int val) { this.val = val; }
* TreeNode(int val, TreeNode left, TreeNode right) {
* this.val = val;
* this.left = left;
* this.right = right;
* }
* }
*/
public class Solution {
public TreeNode addOneRow(TreeNode root, int val, int depth) {
if (depth == 1) {
TreeNode newRoot = new TreeNode(val);
newRoot.left = root;
return newRoot;
}
dfs(root, depth - 2, val);
return root;
}
private void dfs(TreeNode node, int depth, int val) {
if (depth == 0) {
TreeNode left = new TreeNode(val);
TreeNode right = new TreeNode(val);
left.left = node.left;
right.right = node.right;
node.left = left;
node.right = right;
} else {
if (node.left != null) {
dfs(node.left, depth - 1, val);
}
if (node.right != null) {
dfs(node.right, depth - 1, val);
}
}
}
}