- published: 31 Mar 2016
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In computer science, A* (pronounced "A star" (listen)) is a computer algorithm that is widely used in pathfinding and graph traversal, the process of plotting an efficiently traversable path between points, called nodes. Noted for its performance and accuracy, it enjoys widespread use. Peter Hart, Nils Nilsson and Bertram Raphael of Stanford Research Institute (now SRI International) first described the algorithm in 1968. It is an extension of Edsger Dijkstra's 1959 algorithm. A* achieves better performance (with respect to time) by using heuristics.
A* uses a best-first search and finds a least-cost path from a given initial node to one goal node (out of one or more possible goals).
It uses a distance-plus-cost heuristic function (usually denoted Failed to parse (Missing texvc executable; please see math/README to configure.): f(x) ) to determine the order in which the search visits nodes in the tree. The distance-plus-cost heuristic is a sum of two functions:
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The Failed to parse (Missing texvc executable; please see math/README to configure.): h(x)
William Leonard Roberts II (born January 28, 1976), better known by his stage name Rick Ross (often stylized as RICK RO$$), is an American rapper. He derived his stage name from the drug trafficker "Freeway" Ricky Ross, to whom he has no connection. Ross founded the record label Maybach Music Group, on which he released his studio albums Deeper Than Rap and Teflon Don, Ross was also the first artist signed to Diddy's management company Ciroc Entertainment. In early 2012, MTV named Ross as the Hottest MC In The Game.
William Leonard Roberts II was born in Coahoma County, Mississippi. and raised in Carol City, Florida, near Miami. After graduating from Carol City Senior High School, he later attended the historically black college Albany State University on a football scholarship.
After being signed to Suave House Records, former label for rap duo 8Ball & MJG, he eventually signed a deal with Slip-n-Slide Records, which has been under the Def Jam umbrella since 2006. While signed to Slip-n-Slide, Ross toured with fellow rapper Trick Daddy and made guest performances on other Slip-n-Slide albums.
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As a solo musical artist, Lovato released her debut album Don't Forget on September 23, 2008. The album debuted at number two on the Billboard 200 selling 89,000 copies in the first week. It has since shipped over 500,000 copies, earning a gold certification in the United States. Lovato released her second album, Here We Go Again, on July 21, 2009. The album debuted at number one on the Billboard 200, selling 108,000 copies in the first week. Her third studio album, Unbroken, was released on September 20, 2011 and peaked at number four on the Billboard 200. She is working on her fourth studio album.