Alternate sums
C_K_Yang Walker czp001 liuguangxi a_forsteri Min_25 C3PO Philippe_57721 gerrob mathpseudo sinan hervas benito255 lesnik7 clytorock nielkh
Public  04/28/17  4xp  Math  69.6% 
How many different values can the expression $ 1 \pm 2 \pm 3 \pm \dots \pm n$ take?
Give your answer for $n = 1000000$
[My timing: instant]
Give your answer for $n = 1000000$
[My timing: instant]
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