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Md Ariful Haque @mah-shamim

Minimum Cost To Make At Least One Valid Path In A Grid

Modify signs in m x n grid to create a valid path from top-left to bottom-right using 0-1 BFS with deque & distance array, achieving min cost of O(m × n) time & space complexity.

1368. Minimum Cost to Make at Least One Valid Path in a Grid
Difficulty: Hard
Topics: Array, Breadth-First Search, Graph, Heap (Priority Queue), Matrix, Shortest Path
Given an m x n grid. Each cell of the grid has a sign pointing to the next cell you should visit if you are currently in this cell. The sign of grid[i][j] can be:

1 which means go to the cell to the right. (i.e go from grid[i][j] to grid[i][j + 1])
2 which means go to the cell to the left. (i.e go from grid[i][j] to grid[i][j - 1])
3 which means go to the lower cell. (i.e go from grid[i][j] to grid[i + 1][j])
4 which means go to...