Serialize and Deserialize Binary Tree
Design an algorithm to serialize and deserialize a binary tree into a string.
public class Codec {
// Encodes a tree to a single string.
public String serialize(TreeNode root) {
if(root == null){
return "";
}
return dfs(root);
}
StringBuilder sb = new StringBuilder();
public String dfs(TreeNode node){
if(node == null){
sb.append("null, ");
return "";
}
sb.append(node.val + ", ");
dfs(node.left);
dfs(node.right);
return sb.toString();
}
// Decodes your encoded data to tree.
public TreeNode deserialize(String data) {
if(data.equals("")){
return null;
}
String arr[] = data.split(", ");
return construct(arr);
}
int idx = 0;
public TreeNode construct(String arr[]){
if(idx >= arr.length || arr[idx].equals("null")){
idx++;
return null;
}
TreeNode node = new TreeNode(Integer.parseInt(arr[idx++]));
node.left = construct(arr);
node.right = construct(arr);
return node;
}Related Problems
Given a string S and an integer K, return the length of the longest substring of S that contains at most K distinct characters.
Given an integer array nums, you need to find one continuous subarray such that if you only sort this subarray in non-decreasing order, then the whole array will be sorted in non-decreasing order.
Return the shortest such subarray and output its length.
Given two strings s and t of lengths m and n respectively, return the minimum window
substringof s such that every character in t (including duplicates) is included in the window. If there is no such substring, return the empty string "".
The testcases will be generated such that the answer is unique.
Write a program to solve a Sudoku puzzle by filling the empty cells.
A sudoku solution must satisfy all of the following rules:
Each of the digits 1-9 must occur exactly once in each row.
Each of the digits 1-9 must occur exactly once in each column.
Each of the digits 1-9 must occur exactly once in each of the 9 3x3 sub-boxes of the grid.
The '.' character indicates empty cells.