Create 752-Open-the-Lock.py

Author: neetcode-gh

752-Open-the-Lock.py

@@ -0,0 +1,26 @@
+class Solution:
+    def openLock(self, deadends: List[str], target: str) -> int:
+        if "0000" in deadends:
+            return -1
+        
+        def children(wheel):
+            res = []
+            for i in range(4):
+                digit = str((int(wheel[i]) + 1) % 10)
+                res.append(wheel[:i] + digit + wheel[i+1:])
+                digit = str((int(wheel[i]) + 10 - 1) % 10)
+                res.append(wheel[:i] + digit + wheel[i+1:])
+            return res    
+                
+        q = deque()
+        visit = set(deadends)
+        q.append(["0000", 0]) # [wheel, turns]
+        while q:
+            wheel, turns = q.popleft()
+            if wheel == target:
+                return turns
+            for child in children(wheel):
+                if child not in visit:
+                    visit.add(child)
+                    q.append([child, turns + 1])
+        return -1