The adjacency matrix`adj[][]` of size $n \times n$ stores the weights of the edges, and it uses the weight`INF` if there doesn't exist an edge between two vertices.

The algorithm uses two arrays: the flag`selected[]`, which indicates which vertices we already have selected, and the array`min_e[]` which stores the edge with minimal weight toan selected vertex for each not-yet-selected vertex (it stores the weight and the end vertex).

The algorithm uses two arrays: the flag`selected[]`, which indicates which vertices we already have selected, and the array`min_e[]` which stores the edge with minimal weight toa selected vertex for each not-yet-selected vertex (it stores the weight and the end vertex).

The algorithm does $n$ steps, in each iteration the vertex with the smallest edge weight is selected, and the`min_e[]` of all other vertices gets updated.