Weighted graph

... a $n \times n$ matrix $A$ where $A[i, j]$ is equal to 0 if there is an edge between $i$ and $j$ and to $1$ otherwise.

... a $n \times n$ matrix $A$ where $A[i, j]$ is equal to 1 if there is an edge between $i$ and $j$ and to $0$ otherwise.

... a $n \times n$ matrix $A$ where $A[i, j]$ is equal to the weight of an edge between $i$ and $j$ (if exists) and $0$ otherwise.

... a $n \times n$ matrix $A$ where $A[i, j]$ is equal to the weight of an edge between $i$ and $j$ (if exists) and to $\infty$ or $0$ otherwise.