10 lines
275 B
Python
10 lines
275 B
Python
''' Starting in the top left corner of a 2*2 grid, there are 6 routes (without backtracking) to the bottom right corner.
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How many routes are there through a 20*20 grid? '''
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total = 1
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for i in xrange(40, 20, -1):
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total *= i
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for i in xrange(1, 21):
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total /= i
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print total
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