# Re: find a number

*From*: Sc0rpi0 <sc0rpi0@xxxxxxxxxxxxxx>*Date*: Thu, 30 Mar 2006 15:25:07 +0200

CBFalconer:

s = 0; i = 0;

do {

s -= i;

s += a[i++];

} while (i <= 1001);

minor optim.:

s = 0; i = 1(0);

while (i<1002(1001)) s+=a[i++];

s-=500500; (or (1000+1)*1000/2 - Gauss ;P, but precalculated is better)

printf("duplicate is %d\n", s);

--

Sc0rpi0

I hated going to weddings.

All the grandmas would poke me saying "You're next".

They stopped that when I started doing it to them at funerals.

.

**References**:**find a number***From:*murali@pune

**Re: find a number***From:*Sc0rpi0

**Re: find a number***From:*Mark P

**Re: find a number***From:*Arthur J. O'Dwyer

**Re: find a number***From:*CBFalconer

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