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Practice Open the Lock

Read the task, work through the examples, and check your approach against the constraints. Use the original LeetCode task for coding and submissions.

Medium#752
LeetCode Problem

Open the Lock

Problem Statement

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.

Source: Open the Lock on LeetCode. Use the original task for its coding environment and submissions.

Examples

# Example 1

Input
deadends = ["0201","0101","0102","1212","2002"], target = "0202"
Output
6

# Example 2

Input
deadends = ["8888"], target = "0009"
Output
1

# Example 3

Input
deadends = ["8887","8889","8878","8898","8788","8988","7888","9888"], target = "8888"
Output
-1

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.

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