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rampatrarampatra
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IsomorphicStrings: done
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‎src/main/java/com/leetcode/graphs/WordLadder.java

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Original file line numberDiff line numberDiff line change
@@ -102,8 +102,20 @@ public static int ladderLength(String beginWord, String endWord, List<String> wo
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return 0;
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}
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/**
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* TODO: Optimized both end BFS solution
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*
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* @param beginWord
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* @param endWord
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* @param wordList
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* @return
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*/
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public static int ladderLengthOptimized(String beginWord, String endWord, List<String> wordList) {
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return -1;
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}
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public static void main(String[] args) {
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assertEquals(5, ladderLength("hit", "cog", Arrays.asList("hot", "dot", "dog", "lot", "log", "cog")));
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assertEquals(0, ladderLength("hit", "cog", Arrays.asList("hot", "dot", "dog", "lot", "log")));
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}
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}
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}

‎src/main/java/com/leetcode/trees/SerializeDeserializeBinaryTree.java

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@@ -0,0 +1,179 @@
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package com.leetcode.trees;
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import java.util.LinkedList;
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import java.util.Queue;
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/**
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* Level: Hard
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* Link: https://leetcode.com/problems/serialize-and-deserialize-binary-tree/
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* Description:
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* Serialization is the process of converting a data structure or object into a sequence of bits so that it can be
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* stored in a file or memory buffer, or transmitted across a network connection link to be reconstructed later in
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* the same or another computer environment.
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*
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* Design an algorithm to serialize and deserialize a binary tree. There is no restriction on how your
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* serialization/deserialization algorithm should work. You just need to ensure that a binary tree can be serialized
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* to a string and this string can be deserialized to the original tree structure.
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*
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* Example:
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*
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* You may serialize the following tree:
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*
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* 1
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* / \
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* 2 3
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* / \
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* 4 5
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*
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* as "[1,2,3,null,null,4,5]"
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*
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* Clarification: The above format is the same as how LeetCode serializes a binary tree. You do not necessarily need
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* to follow this format, so please be creative and come up with different approaches yourself.
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*
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* Note: Do not use class member/global/static variables to store states. Your serialize and deserialize algorithms
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* should be stateless.
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*
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* @author rampatra
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* @since 2019-08-17
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*/
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public class SerializeDeserializeBinaryTree {
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/**
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* Runtime: <a href="https://leetcode.com/submissions/detail/252443769/">31 ms</a>.
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*
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* @param root
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* @return
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*/
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public static String serialize(TreeNode root) {
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if (root == null) {
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return "[]";
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}
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StringBuilder sb = new StringBuilder();
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sb.append("[");
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Queue<TreeNode> queue = new LinkedList<>();
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queue.add(root);
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while (!queue.isEmpty()) {
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TreeNode node = queue.poll();
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if (sb.length() > 1) {
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sb.append(", ");
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}
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if (node == null) {
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sb.append("null");
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continue;
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}
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sb.append(node.val);
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queue.add(node.left);
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queue.add(node.right);
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}
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sb.append("]");
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return removeExtraNulls(sb.toString());
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}
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private static String removeExtraNulls(String data) {
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int i = data.length() - 1;
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while (!(data.charAt(i) >= 48 && data.charAt(i) <= 57)) {
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i--;
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}
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return data.substring(0, i + 1) + "]";
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}
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/**
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*
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* @param data
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* @return
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*/
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public static TreeNode deserialize(String data) {
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data = data.substring(1, data.length() - 1);
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if (data.length() == 0) {
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return null;
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}
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String[] values = data.split(", ");
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TreeNode root = new TreeNode(Integer.parseInt(values[0]));
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Queue<TreeNode> queue = new LinkedList<>();
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queue.add(root);
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for (int i = 0; i < values.length && !queue.isEmpty(); i += 2) {
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TreeNode currNode = queue.poll();
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if (i + 1 < values.length && !values[i + 1].equals("null")) {
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TreeNode leftNode = new TreeNode(Integer.parseInt(values[i + 1]));
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currNode.left = leftNode;
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queue.add(leftNode);
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}
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if (i + 2 < values.length && !values[i + 2].equals("null")) {
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TreeNode rightNode = new TreeNode(Integer.parseInt(values[i + 2]));
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currNode.right = rightNode;
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queue.add(rightNode);
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}
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}
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return root;
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}
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public static void main(String[] args) {
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// TODO Convert the print statements to asserts
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System.out.println(serialize(new TreeNode(1)));
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/*
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Binary Tree
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1
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/ \
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2 3
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/ \
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4 5
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*/
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TreeNode tree = new TreeNode(1);
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tree.left = new TreeNode(2);
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tree.right = new TreeNode(3);
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tree.left.left = new TreeNode(4);
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tree.left.right = new TreeNode(5);
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System.out.println(serialize(tree));
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System.out.println(serialize(deserialize(serialize(tree))));
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System.out.println(serialize(deserialize(serialize(null))));
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TreeNode tree2 = new TreeNode(1);
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tree2.right = new TreeNode(2);
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tree2.right.right = new TreeNode(3);
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tree2.right.right.right = new TreeNode(4);
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tree2.right.right.right.right = new TreeNode(5);
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tree2.right.right.right.right.right = new TreeNode(6);
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tree2.right.right.right.right.right.right = new TreeNode(7);
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tree2.right.right.right.right.right.right.right = new TreeNode(8);
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System.out.println(serialize(tree2));
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System.out.println(serialize(deserialize(serialize(tree2))));
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System.out.println("---");
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System.out.println(serialize(deserialize("[1, 2]")));
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System.out.println(serialize(deserialize("[1, 2, 3]")));
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System.out.println(serialize(deserialize("[3, 2, 4, 1]")));
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System.out.println(serialize(deserialize("[3, 2, 4, 1, 5, 6]")));
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System.out.println(serialize(deserialize("[1, 2, 3, null, null, 4, 5]")));
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System.out.println(serialize(deserialize("[5, 2, 3, null, null, 2, 4, 3, 1]")));
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System.out.println(serialize(deserialize("[1, null, 2, null, 3, null, 4, null, 5]")));
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System.out.println(serialize(deserialize("[1, null, 2, null, 3, null, 4, null, 5, null, 6]")));
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System.out.println(serialize(deserialize("[1, null, 2, null, 3, null, 4, null, 5, null, 6, null, 7]")));
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System.out.println(serialize(deserialize("[1, null, 2, null, 3, null, 4, null, 5, null, 6, null, 7, null, 8]")));
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System.out.println(serialize(deserialize("[1, null, 2, null, 3, null, 4, null, 5, null, 6, null, 7, null, 8, null, 9]")));
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}
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}

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