@Piyush: I think not. Try n = 17 = 4*4 + 1 or n = 19 = 4*4 + 3. But you can
say that n = 4 * a + b, with 0 <= b <= 3, is a multiple of 5 if and only if
a - b is a multiple of 5, thus reducing to a simpler problem. That's the
basis of the solution I posted earlier in this string.
Dave
On Saturday, October 13, 2012 3:58:16 PM UTC-5, Piyush Grover... wrote:
> The number which has 5 as last digit can be written as
> n = 4*a + b where b = 1 or 3
> so if 4*a + 1 == n or 4*a + 3 == n; then n has 5 as a last digit.
> So code looks like:
>
> void main()
> {
> int n, m;
> scanf("%d", &n);
> m >>= 2;
> m <<= 2;
> if(add(m, 1) == n || add(m,3) == n)
> puts("yes");
> else
> puts("no");
> }
>
> int add(int x, int y) {
>
> int a, b;
>
> do {
>
> a = x & y; b = x ^ y; x = a << 1; y = b;
>
> }while(b);
>
> return b;
>
> }
>
>
> On Fri, Oct 12, 2012 at 12:46 AM, Dave <[email protected]
> <javascript:>>wrote:
>
>> @Jaspreet: The % operator is implemented using division, which is
>> considered an arithmetic operation, not a bitwise operation.
>>
>> On primitive chips, as may be used in specialized hardware, division may
>> not be implemented, in which case a non-division based algorithm may be
>> desired.
>>
>> The question may be based on that idea, or just on how to do it faster
>> than using division, which typically is a very slow instruction (compared
>> to other machine instructions).
>>
>> Dave
>>
>> On Thursday, October 11, 2012 4:14:17 AM UTC-5, Jaspreet Singh wrote:
>>
>>> Nice solution Dave sir .. but if you know can you please tell us what is
>>> the internal structure of "%" operator .. i mean it has also to be done by
>>> bitwise any way .. so can't we implement that in HHLs.
>>>
>>> Thanks
>>>
>>> On Thu, Oct 11, 2012 at 1:25 AM, Dave <[email protected]> wrote:
>>>
>>>> @Mohit: The decimal representation of a number ends in 5 if its low
>>>> order bit is 1 and it is divisibile by 5.
>>>>
>>>> An algorithm using bitwise operations to check for divisibility by 5 is
>>>> given at https://groups.google.com/d/**msg/algogeeks/I5HWmwKW_ks/**
>>>> n38FWJSd0l8J<https://groups.google.com/d/msg/algogeeks/I5HWmwKW_ks/n38FWJSd0l8J>.
>>>>
>>>>
>>>>
>>>> It probably is not as fast as (n & 1) && (n % 5 == 0), though.
>>>>
>>>> Dave
>>>>
>>>> On Wednesday, October 10, 2012 4:06:28 AM UTC-5, mohit mishra wrote:
>>>>
>>>>>
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