Grid BFS: Minimum steps in a 2D matrix (simplified interview variant)

Coding: Minimum steps in a 2D grid (BFS) You are given a 2D matrix grid where: grid[r][c] = 0 means the cell is walkable grid[r][c] = 1 means the cell is blocked You are also given a start cell S = (sr, sc) and a target cell T = (tr, tc). In one step, you may move to one of the 4-directionally adjacent cells (up/down/left/right). You may not leave the grid or step onto blocked cells. Return the minimum number of steps required to reach T from S. If it is impossible, return -1. Input (stdin) Line 1: two integers m n Next m lines: n integers (0/1) describing grid Next line: sr sc (start) Next line: tr tc (target) Output (stdout) One integer: minimum steps or -1 Constraints 1 <= m, n <= 200 Test cases Example Input 3 3 0 0 0 1 1 0 0 0 0 0 0 2 2 Output 4