From 5c05e0476627a5707779db7b72a532ac158cd442 Mon Sep 17 00:00:00 2001
From: ATRI2107 <atrichaturvedi@gmail.com>
Date: Fri, 9 Oct 2020 23:17:26 +0530
Subject: [PATCH 1/3] Added the file

---
 Java/word-ladder.java | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 Java/word-ladder.java

diff --git a/Java/word-ladder.java b/Java/word-ladder.java
new file mode 100644
index 00000000..e69de29b

From 73cfef37cfd2578ecffe69d36326198d4897e1f1 Mon Sep 17 00:00:00 2001
From: ATRI2107 <atrichaturvedi@gmail.com>
Date: Fri, 9 Oct 2020 23:22:11 +0530
Subject: [PATCH 2/3] Added word-ladder program

---
 Java/word-ladder.java | 57 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/Java/word-ladder.java b/Java/word-ladder.java
index e69de29b..ac66c80c 100644
--- a/Java/word-ladder.java
+++ b/Java/word-ladder.java
@@ -0,0 +1,57 @@
+/*
+Given two words (beginWord and endWord), and a dictionary's word list, find the length of shortest transformation sequence from beginWord to endWord, such that:
+
+Only one letter can be changed at a time.
+Each transformed word must exist in the word list.
+Note:
+
+Return 0 if there is no such transformation sequence.
+All words have the same length.
+All words contain only lowercase alphabetic characters.
+You may assume no duplicates in the word list.
+You may assume beginWord and endWord are non-empty and are not the same.
+
+Problem Link:  https://leetcode.com/problems/word-ladder/
+It is a popular interview program which is based on BFS
+*/
+import java.util.*;
+class Solution {
+    public int ladderLength(String beginWord, String endWord, List<String> wordList) {
+        HashSet<String> hs=new HashSet<>(wordList);
+        if(!hs.contains(endWord))
+        {
+            return 0;
+        }
+        int steps=1;
+        Queue<String> q=new LinkedList<>();
+        q.add(beginWord);
+        while(!q.isEmpty())
+        {
+            int count=q.size();
+            for(int i=0;i<count;i++)
+            {
+                String curr=q.poll();
+                char a[]=curr.toCharArray();
+                for(int j=0;j<a.length;j++)
+                {
+                    char temp=a[j];
+                    for(char c='a';c<='z';c++)
+                    {
+                        if(a[j]==c) continue;
+                        a[j]=c;
+                        String test=new String(a);
+                        if(test.equals(endWord)) return steps+1;
+                        if(hs.contains(test))
+                        {
+                            q.add(test);
+                            hs.remove(test);
+                        }
+                    }
+                    a[j]=temp;
+                }
+            }
+            steps++;
+        }
+        return 0;
+    }
+}
\ No newline at end of file

From bbad7a232aacd85019cd5837b30775001a7bbf6c Mon Sep 17 00:00:00 2001
From: Atri Chaturvedi <atrichaturvedi@gmail.com>
Date: Sat, 10 Oct 2020 21:11:26 +0530
Subject: [PATCH 3/3] Update README.md

---
 README.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/README.md b/README.md
index 1ddd6a1a..416d5a26 100644
--- a/README.md
+++ b/README.md
@@ -253,6 +253,7 @@ Check out ---> [Sample PR](https://github.com/codedecks-in/LeetCode-Solutions/pu
 | ---- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------- | ------------------------- | ----------------- | ---------- | --- | ---- |
 | 1284 | [Minimum Number of Flips to Convert Binary Matrix to Zero Matrix](https://leetcode.com/problems/minimum-number-of-flips-to-convert-binary-matrix-to-zero-matrix/) | [C++](./C++/Minimum-Number-of-Flips-to-Convert-Binary-Matrix-to-Zero-Matrix.cpp) | _O(m * n * 2 ^ (m \* n))_ | _O(2 ^ (m \* n))_ | Hard       | BFS |      |
 | 200  | [Number of Islands](https://leetcode.com/problems/number-of-islands/)                                                                                             | [Java](./Java/NumberOfIslands.java)                                              | O(R \* C)                 | O(R \* C)         | Medium     | BFS |
+| 200  | [Word Ladder](https://leetcode.com/problems/word-ladder/)                                                                                             | [Java](./Java/word-ladder.java)                                              | O(N^2 \* M)                 | O(N \* M)         | Medium     | BFS |
 
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