By Sergio Goncalves, Catarina Demony and Andrei Khalip MADRID (Reuters) -Portugal's ruling centre-right Democratic Alliance (AD) won a snap parliamentary election on Sunday but again fell short of the majority needed to end a long period of instability as the far-right Chega gained a record share of the vote.

Portugal is a parliamentary republic with a unicameral legislature of 230 members, elected by direct vote to serve four-year terms. On March 13, President Marcelo Rebelo de Sousa dissolved parliament and called a snap election for May 18, marking the country's third early parliamentary election in less than four years.