Question

We have a history of match result of pingpong games, assume each match is <player1, player2, result, timestamp>, player1 and player2 are long type, result is a bit value (1 means player1 win).

design a algorithm to sort the players by their possibility to win future games.

Solution

For each play,

winning score = score_diff * {delay factor^{current time - winning time}};

Pagerank

PageRank is what Google uses to determine the importance of a web page.

It determines which pages appear in search results.

Named after Larry Page.

Details

1. PageRank thinks of links as votes to another page.

2. It also looks at the importance of the page that contains the link.

   1. Pages with higher PageRank have more weight in “voting”.

   2. Pages with smaller total number of links on the page have more weight.

Increase your PageRank?

If you’d like to increase your PageRank, you need to have “back-links,” or other people linking to your website. You can trade links with other people, but make sure you only trade relevant links, and make sure you’re not trading links with a link farm.

You can register your website with directories, such as the Open Directory Project, but use directories with high PageRank whenever possible.

You can create some of your own back-links by linking to relevant pages within your own website. However, remember that the number of links you create counts into the equation. Don’t overdo it.