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zylum

Fri Mar 04, 2005 5:12 pm


[CCC 2005] Senior S5: Pinball Ranking

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Pinball is an arcade game in which an individual player contrils a silver ball by means of flippers, with the objective of accumilating as many points as possible. At the end of each game, the player's score and rank are displayed. The score, an integer betwee 0 and 1 000 000 000, is that achieved by the player in the game just ended. The rank is displayed as "r of n". n is the total number of games ever played on the machine, and r is the position of the score for the just-ended game within this set. More precisely, r is one greater than the number of games whose score exceeds that of the game just ended.

Your are to implement the pinball machine's ranking algorithm. The first line of input contains a positive integer, t, the total number of games played in the lifetime of the machine. t lines follow, given the scores of these games, in chronological order. Input contained in the file s5.in.

Your are to output the average of the ranks (rounded to two digits after the decimal) that would be displayed on the board. 

At least one test case will have t