31 lines
630 B
Python
31 lines
630 B
Python
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import sys, os
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I = list(map(int, sys.stdin.read().strip()))
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def sum_n(a, b):
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return (b-a+1)*(a+b)//2
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idxs = []
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b = 0
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for i in I:
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idxs.append(b)
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b += i
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res = 0
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id = len(I)//2 # last id
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for j in range(len(I)-1,-1,-2): # backward
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fsize = I[j]
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for i in range(1, j, 2): # find free space forward
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if I[i] >= fsize: # enough free space
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b = idxs[i]
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res += sum_n(b, b+fsize-1)*id
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idxs[i] += fsize
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I[i] -= fsize
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break
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else: # block too big stays where it is
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b = idxs[j]
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res += sum_n(b, b+fsize-1)*id
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id -= 1
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print(res)
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