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DIY: Open Lock

Explore how to determine the minimum number of wheel turns needed to open a lock with four rotating wheels, avoiding deadend states. Learn to model the problem, apply breadth-first search, and handle constraints to develop efficient solutions. This lesson helps you master practical problem-solving techniques used in coding interviews.

Problem statement

You have an old lock in front of you with four circular wheels. Each wheel has ten 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 ...