Unique Path II 🌟🌟

• This Problem is same as previous unique path problem, But here we need to add one condition for -1 element.
• If we encounter -1 element then we can’t go further in that direction, so we return 0.
• write If(mat[i][j]==-1) return 0; after checking if indexes are not out of bound.
• All solution passes with this extra case.