Is the word deixou the same in Brazilian and European Portuguese?

Yes.

The word "deixou" is identical in meaning, spelling, and grammatical function in both Brazilian and Continental Portuguese. The only difference is phonetic: in Brazil, the "e" is typically pronounced as a mid-vowel [e], whereas in Portugal, it is often reduced to a much more closed or even a schwa-like sound [ɨ].

Brazilian Portuguese Examples

1. Ele deixou o celular no ônibus. (He left his cell phone on the bus.)
2. Ela deixou o sorvete derreter no sol. (She let the ice cream melt in the sun.)
3. O trem deixou o passageiro na estação. (The train left the passenger at the station.)
4. Ele deixou o computador ligado. (He left the computer on.)
5. Ela deixou o cachorro sair no quintal. (She let the dog go out in the yard.)

Continental Portuguese Examples

1. Ele deixou o telemóvel no autocarro. (He left his mobile phone on the bus.)
2. Ela deixou o gelado derreter ao sol. (She let the ice cream melt in the sun.)
3. O comboio deixou o passageiro na estação. (The train left the passenger at the station.)
4. Ele deixou o computador ligado. (He left the computer on.)
5. Ela deixou o cão sair no quintal. (She let the dog go out in the yard.)