# dict_sortnearest.py

# dict_sortnearest.py

lista = [16,11,24,25]
dica = {'a':[10],'b':[20],'c':[30]}

k,v = zip(*[(dica[k][0],k) for k in dica])
for num in lista:
    z = [abs(x-num) for x in k]
    dica[v[z.index(min(z))]].append(num)
print(dica)

# ... or a faster way for Python to process as by only indexing...
dica = {0:[10],1:[20],2:[30]}

k = [dica[k][0] for k in dica]
for num in lista:
    z = [abs(x-num-1) for x in k]
    dica[z.index(min(z))].append(num)
print(dica)