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

No.

While the core dictionary definitions of "altos" (tall, high, or loud) are identical in both dialects, there is a difference in typical usage. In Brazilian Portuguese, especially in informal or slang contexts, "altos" is frequently used as a quantifier or intensifier to mean "a lot of," "many," or "very great." In Continental Portuguese, this usage is not standard; a Portuguese speaker would typically replace "altos" with "muitos" (many) or "grandes" (great/large) to express the same idea.

Brazilian Portuguese Examples

1. Ele tem altos problemas para resolver. (He has a lot of problems to solve.)
2. A festa teve altos momentos de alegria. (The party had great moments of joy.)
3. Os preços da carne estão muito altos. (The meat prices are very high.)
4. Aqueles jogadores são muito altos. (Those players are very tall.)
5. Os volumes das caixas são muito altos. (The volumes of the boxes are very high.)

Portuguese (Portugal) Examples

1. Ele tem muitos problemas para resolver. (He has many problems to solve.)
2. A festa teve grandes momentos de alegria. (The party had great moments of joy.)
3. Os preços da carne estão muito altos. (The meat prices are very high.)
4. Aqueles jogadores são muito altos. (Those players are very tall.)
5. Os volumes das caixas são muito altos. (The volumes of the boxes are very high.)