Is my circuit diagram correct ?

[anacondaonline]

I am drawing a circuit diagram from a minimize expression. I have come up with two circuit diagrams that give same result.
I am not sure which of the circuit diagram (1) or (2) is correct. Are both my diagram correct? Need help

 

[Harald Kapp]

1) Both diagrams are correct. Can you explain why they are equivalent? Hint: there is only one difference in terms of gates used which explains this. This difference requires that one of the input signals is already correctly preconditioned.

2) Your expression j = ad + /bd (/b means not b, I cannot put an overbar here) is "minimized" only under the condition that you are allowed to use NAND gates only. If you are allowed to use other types of gates too, the expression can be further simplified and the upper circuit would use 3 gates (instead of 4) and the lower circuit would use 2 gates (instead of 3). Hint: Use the distributive property of Boolean algebra.