3, 2, 1, Go!

Computer Science Level 3

$\large { {2016 \, 2015 \, 2014 \ldots 4 \, 3 \, 2 \, 1} }$

The above expression shows the concatenation of the first $2016$ positive integers written backwards.

Let $L$ and $S$ denote the number of digits and the sum of digits, respectively, of this large number. Compute $\dfrac1{10} \left[ (S-L) \pmod{2016} \right].$

The answer is 99.

1 solution

Hjalmar Orellana Soto
Feb 16, 2016

a=2016

b=a

while a>1:

_ _a-=1

_ _b=str(b)+str(a)

L=len(str(b))

c=0

d=0

while c<L:

_ _d+=int(str(b)[c])

_ _c+=1

S=d

print 0.1*((S-L)%2016)

3, 2, 1, Go!

The answer is 99.

1 solution

a=2016

b=a

while a>1:

_ _a-=1

_ _b=str(b)+str(a)

L=len(str(b))

c=0

d=0

while c<L:

_ _d+=int(str(b)[c])

_ _c+=1

S=d

print 0.1*((S-L)%2016)

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