f.nasim's blog

Round#11 problem B
By f.nasim, 15 years ago, In English
Can anyone tell actually what's the behind that problem.I proved many individual cases but didn't find any formula or pattern, except for the numbers given by n(n+1)/2.
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15 years ago, # |
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It's quite easy to prove by induction that the set of points accessible after n jumps is {-n(n+1)/2, -n(n+1)/2 + 2, ... , n*(n+1)/2-2, n*(n+1)/2}. Just move this set by (n+1) and -(n+1) and see what happens.
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