Time: 72 ms (93.14%), Space: 14 MB (73.67%) - LeetHub

Author: JanaSabuj

word-ladder/word-ladder.cpp

@@ -0,0 +1,44 @@
+class Solution {
+public:
+       int minLenPath(string& beginWord, string& endWord, vector<string>& wordList) {
+        unordered_set<string> dict(wordList.begin(), wordList.end());
+
+        if (dict.find(endWord) == dict.end())
+            return 0;
+        queue<pair<string, int>> q;
+        q.push({beginWord, 1});
+        dict.erase(beginWord);
+
+        while (!q.empty()) {
+            auto x = q.front();
+            q.pop();
+
+            if (x.first == endWord)
+                return x.second;
+
+            // check its children
+            string curr = x.first;
+            for (int i = 0; i < (int)curr.size(); i++) {
+                char old = curr[i];
+
+                for (int j = 0; j < 26; j++) {
+                    if ((j + 'a') == old) continue;
+                    curr[i] = (j + 'a');
+
+                    if (dict.find(curr) != dict.end()) {
+                        q.push({curr, x.second + 1});
+                        dict.erase(curr);
+                    }
+                }
+
+                curr[i] = old;
+            }
+        }
+
+        return 0;
+    }
+    int ladderLength(string beginWord, string endWord, vector<string>& wordList) {
+        int k = minLenPath(beginWord, endWord, wordList);
+        return k;
+    }
+};