Create Word Ladder.cpp

Author: Its-Aman-Yadav

Hard Problems/Word Ladder.cpp

@@ -0,0 +1,34 @@
+//https://leetcode.com/problems/word-ladder/description/
+
+class Solution {
+public:
+    int ladderLength(string beginWord, string endWord, vector<string>& wordList) {
+        unordered_set<string> dict(wordList.begin(), wordList.end());
+        queue<string> todo;
+        todo.push(beginWord);
+        int ladder = 1;
+        while (!todo.empty()) {
+            int n = todo.size();
+            for (int i = 0; i < n; i++) {
+                string word = todo.front();
+                todo.pop();
+                if (word == endWord) {
+                    return ladder;
+                }
+                dict.erase(word);
+                for (int j = 0; j < word.size(); j++) {
+                    char c = word[j];
+                    for (int k = 0; k < 26; k++) {
+                        word[j] = 'a' + k;
+                        if (dict.find(word) != dict.end()) {
+                            todo.push(word);
+                        }
+                     }
+                    word[j] = c;
+                }
+            }
+            ladder++;
+        }
+        return 0;
+    }
+};