752. Open the Lock
题目描述
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:
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Example 2:
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Example 3:
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Example 4:
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Note:
- The length of deadends will be in the range [1, 500].
- target will not be in the list deadends.
- Every string in deadends and the string target will be a string of 4 digits from the 10,000 possibilities ‘0000’ to ‘9999’.
题目大意
密码锁解锁,从 0000
开始,移动每个齿轮,直到匹配到目标数字组合,求需要移动的步数。
其中 deadends
表示不能够访问的数字组合; 0
可以转到 9
, 9
也可以转到 0
。
解题思路
BFS
代码
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