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

Yes

The word "comeu" is identical in both Brazilian and Continental Portuguese in terms of spelling, grammar (third-person singular, preterite indicative of the verb comer), and meaning. The only differences between the two dialects are phonetic. In Brazilian Portuguese, vowels tend to be more open and the rhythm is more syllable-timed. In Continental Portuguese, unstressed vowels are often more reduced, closed, or nearly swallowed, making the word sound slightly more "clipped."

Brazilian Portuguese Examples

1. Ele comeu todo o bolo sozinho. (He ate the whole cake alone.)
2. O cachorro comeu o meu chinelo. (The dog ate my flip-flop.)
3. Ela comeu muito no almoço. (She ate a lot at lunch.)
4. Você comeu o seu lanche? (Did you eat your snack?)
5. A criança comeu a maçã rapidinho. (The child ate the apple very quickly.)

Continental Portuguese Examples

1. Ele comeu todo o bolo sozinho. (He ate the whole cake alone.)
2. O cão comeu o meu chinelo. (The dog ate my flip-flop.)
3. Ela comeu imenso ao almoço. (She ate a lot at lunch.)
4. Tu comeste o teu lanche? (Did you eat your snack?)
5. A criança comeu a maçã depressa. (The child ate the apple quickly.)