Finds the number of disconnected components in a graph.

disconnected_components_in_graph.py

def number_of_disconnected_components(self, adj: List[List[int]]) -> int:        
      n = len(adj)

      visited = set()
      components = 0

      for i in range(n):
          if i not in visited:
              visited |= {i}
              components += 1

              stack = [i]

              while stack:
                  node = stack.pop(-1)

                  for j in range(n):
                      if adj[node][j] and j not in visited:
                          stack.append(j)
                          visited |= {j}

      return components