Bottom post of the previous page:
For those who want the detailed explanation:-"Instant-runoff voting (IRV) is a voting method used in single-seat elections with more than two candidates. Instead of voting only for a single candidate, voters in IRV elections can rank the candidates in order of preference. Ballots are initially counted for each elector's top choice, losing candidates are eliminated, and ballots for losing candidates are redistributed until one candidate is the top remaining choice of a majority of the voters. "
There's also Single Transferable Vote:
"The single transferable vote (STV) is a voting system designed to achieve proportional representation through ranked voting in multi-seat organizations or constituencies (voting districts). Under STV, an elector (voter) has a single vote that is initially allocated to their most preferred candidate and, as the count proceeds and candidates are either elected or eliminated, is transferred to other candidates according to the voter's stated preferences, in proportion to any surplus or discarded votes. The exact method of reapportioning votes can vary (see Counting methods).
The system provides approximately proportional representation, enables votes to be cast for individual candidates rather than for parties, and—compared to first-past-the-post voting—reduces "wasted" votes (votes on sure losers or sure winners) by transferring them to other candidates."