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|      \\   / _ \\   /_   _// | || | ||   / ___// 
|  --  //  / //\ \\  `-| |,-  | || | ||   \___ \\ 
|  --  \\ |  ___  ||   | ||   | \\_/ ||   /    // 
|______// |_||  |_||   |_||    \____//   /____//  
`------`  `-`   `-`    `-`'     `---`   `-----`

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Text this: An efficient indexing for top-k query answering in location-based recommendation system