import numpy as np



A = np.array( [np.array([0, 1, 1, 0,0]),
np.array([1, 0, 1,0,0]),
np.array([0,0,0,1,0]),
np.array([0,1,0,0, 1]),
np.array([0,0,0,0,1] ) ]  )




print(A)
print(A[1])
print(A[4])

def brfs(source,dest,Ad):
    result="yes"
    L=len(Ad)
    colour = [0 for k in range(L)]
    q = [source]
    colour[source]==0.5
    while (len(q) >0):
        u = q.pop(0)
        for v in range(L):
            if (A[u][v]==1):
                if (v==dest):
                    return result
                if (colour[v]==0):
                    colour[v]=0.5
                    q.append(v)
        colour[u]=1
    return colour

print(brfs(1,4,A))