Поиск в ширину - BFS

Задачи

https://leetcode.com/problems/shortest-path-in-binary-matrix/description/
https://leetcode.com/problems/all-nodes-distance-k-in-binary-tree/description/
https://leetcode.com/problems/01-matrix/description/
https://leetcode.com/problems/shortest-path-in-a-grid-with-obstacles-elimination/description/
https://leetcode.com/problems/shortest-path-with-alternating-colors/description/
https://leetcode.com/problems/nearest-exit-from-entrance-in-maze/description/
https://leetcode.com/problems/snakes-and-ladders/description/