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вернуться в форумПоказать все сообщения Спрятать все сообщенияI submitted 1068 twice and I always receive "WA"
Then I read about the formula and I compared the
answers(as you can see down) and they were all
the same. Then I submitted the task once again
with the the formula and I got "AC". Can someone
explain why?
var i,sum1,n,sum:longint;
begin
for n:=-10000 to 10000 do
begin
{formula}
if n < 1 then sum := (( 1 + n) * ( 2 - n)) div 2
else if n >=1 then sum := (( n + 1) * n) div 2;
{my solution}
sum1:=0;
if n=1 then sum1:=1
else
if n<=0 then
for i:=1 downto n do sum1:=sum1+i
else
for i:=1 to n do sum1:=sum1+i;
{if there were different answers}
if sum<>sum1 then writeln(n,' ',sum1,' ',sum1); readln;
end;
end. > I submitted 1068 twice and I always receive "WA"
> Then I read about the formula and I compared the
> answers(as you can see down) and they were all
> the same. Then I submitted the task once again
> with the the formula and I got "AC". Can someone
> explain why?
>
> var i,sum1,n,sum:longint;
> begin
> for n:=-10000 to 10000 do
> begin
> {formula}
> if n < 1 then sum := (( 1 + n) * ( 2 - n)) div 2
> else if n >=1 then sum := (( n + 1) * n) div 2;
>
> {my solution}
> sum1:=0;
> if n=1 then sum1:=1
> else
> if n<=0 then
> for i:=1 downto n do sum1:=sum1+i
> else
> for i:=1 to n do sum1:=sum1+i;
>
> {if there were different answers}
> if sum<>sum1 then writeln(n,' ',sum1,' ',sum1); readln;
> end;
>
> end.
> This is not my output this is a program that compares the
two methods of finding the solution
if sum<>sum1 then writeln(n,' ',sum1,' ',sum1); the main reson belongs to the server. Maybe some thing wrong
with compiling
i've submit your solution
var i,sum1,n,sum:longint;
begin
read(n);
{my solution}
sum1:=0;
if n=1 then sum1:=1
else
if n<=0 then
for i:=1 downto n do sum1:=sum1+i
else
for i:=1 to n do sum1:=sum1+i;
writeln(sum1);
end.
and got WA, but when i change it to
var i,sum1,n,sum:longint;
begin
read(n);
{my solution}
sum1:=0;
if n=1 then sum1:=1
else
if n<=0 then
(changing in this line)
for i:=n to 1 do sum1:=sum1+i
else
for i:=1 to n do sum1:=sum1+i;
writeln(sum1);
end.
And i got AC, i don't know why, but maybe the compiler
define that n is always >=1 and it does not run the command
"for i:=1 downto n", so u get WA. So that, don't use "downto
"when not necessary !
Btw, your program will run slower than any program that use
the simple formula.
QH@ |
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