D - Grid Walk

Given an integer grid of size $N\times N$ where a cell in $i^{th}$ row and $j^{th}$ column is specified by pair $(i, j)$, both $0$-indexed. Some cells have obstacles denoted by -1. You are initially at the cell $(0, 0)$ and you can walk in the grid using following rules - - From a cell $(i, j)$ you can move only up, left, right, down one adjacent cell. - You can visit a cell multiple times b