When the context is clear, the noun after the adjective can be omitted. In this case, 的 must be attached to the adjective regardless of the number of characters the adjective has.
妈妈：这里有两条漂亮的裙子；是谁的？
mā mā ：zhè lǐ yǒu liǎng tiáo piāo liàng de qún zǐ ；shì shuí de ？
Mother: There are two pretty skirts here. Whose (skirts) are they?
(漂亮 is disyllabic; 的 is necessary.)
女儿：红的是我的；蓝的是姐姐的。
nǚ ér ：hóng de shì wǒ de ；lán de shì jiě jiě de 。
Daughter: The red one is mine; the blue one is (my) older sister’s.
(裙子 is omitted, so 的 after 红 and 蓝 is necessary.)
[1] Yip, P. C., Rimmington, D., Xiaoming, Z., & Henson, R. (2009). Basic Chinese: a grammar and workbook. Taylor & Francis.
