Package g0701_0800.s0752_open_the_lock

Class Solution

  • public class Solution
extends Object
    752 - Open the Lock\. Medium You have a lock in front of you with 4 circular wheels. Each wheel has 10 slots: `'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'`. The wheels can rotate freely and wrap around: for example we can turn `'9'` to be `'0'`, or `'0'` to be `'9'`. Each move consists of turning one wheel one slot. The lock initially starts at `'0000'`, a string representing the state of the 4 wheels. You are given a list of `deadends` dead ends, meaning if the lock displays any of these codes, the wheels of the lock will stop turning and you will be unable to open it. Given a `target` representing the value of the wheels that will unlock the lock, return the minimum total number of turns required to open the lock, or -1 if it is impossible. **Example 1:** **Input:** deadends = ["0201","0101","0102","1212","2002"], target = "0202" **Output:** 6 **Explanation:** A sequence of valid moves would be "0000" -> "1000" -> "1100" -> "1200" -> "1201" -> "1202" -> "0202". Note that a sequence like "0000" -> "0001" -> "0002" -> "0102" -> "0202" would be invalid, because the wheels of the lock become stuck after the display becomes the dead end "0102". **Example 2:** **Input:** deadends = ["8888"], target = "0009" **Output:** 1 **Explanation:** We can turn the last wheel in reverse to move from "0000" -> "0009". **Example 3:** **Input:** deadends = ["8887","8889","8878","8898","8788","8988","7888","9888"], target = "8888" **Output:** -1 **Explanation:** We cannot reach the target without getting stuck. **Constraints:** * `1 <= deadends.length <= 500` * `deadends[i].length == 4` * `target.length == 4` * target **will not be** in the list `deadends`. * `target` and `deadends[i]` consist of digits only.

    • Constructor Detail

      • Solution

        public Solution()

    • Method Detail

      • openLock

        public int openLock​(String[] deadEnds,
                    String target)