G = [ [0,0,1,0,1,1,0], [0,0,1,1,0,1,0], [1,1,0,1,1,1,0], [0,1,1,0,0,0,0],
      [1,0,1,0,0,0,1], [1,1,1,0,0,0,0], [0,0,0,0,1,0,0] ]

color = [ 0 for i in range(len(G)) ]

color[0] = 1

def coloring(G, current):
    for i in range(len(G)):
         if G[current][i] == 1 and color[i] == 0:
              color[i] = 3 - color[current]
              coloring(G, i)
         elif G[current][i] == 1 and color[i] == color[current]:
              print("Färbung nicht möglich.")
              return

coloring(G, 0)