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10261 - Ferry Loading

Posted: Wed Jun 26, 2002 1:05 pm
by Revenger
I have no idea why my program gets WA :( Can anyone help me?

[pascal]Program p10261;

Const MaxL = 100*100;
MaxC = 5000;
_tr = 'port';
_fa = 'starboard';

Var Inf : array[0..MaxL]of record ok,use : integer end;
Cars,Sum : array[0..MaxC]of integer;
Use : array[1..MaxC]of boolean;
i,j,L,N,ok,k : Integer;
T,TT : Integer;

begin
Read(T);
for TT:=1 to T do begin
if TT>1 then Writeln;
Read(L); L:=L*100; N:=0;
while true do begin
N:=N+1;
Read(Cars[N]);
if Cars[N]=0 then break;
end;
N:=N-1;
for i:=1 to MaxL do Inf.ok:=-1; Inf[0].ok:=0; Sum[0]:=0;
for j:=1 to N do begin
Sum[j]:=Sum[j-1]+Cars[j];
for i:=0 to L-Cars[j] do
if Inf.ok=0 then
if Inf[i+Cars[j]].ok=-1 then
if Sum[j]-i-Cars[j]<=L then begin
Inf[i+Cars[j]].ok:=0;
Inf[i+Cars[j]].use:=j;
ok:=1;
end;
end;
k:=0;
for i:=0 to L do
if Inf.ok=0 then
if Inf.use>Inf[k].use then
k:=i;
Writeln(Output,Inf[k].use);
for i:=1 to Inf[k].use do Use:=false; j:=k;
while true do begin
Use[Inf[j].use]:=true;
j:=j-Cars[Inf[j].use];
if j=0 then break;
end;
for i:=1 to Inf[k].use do
if Use then Writeln(_tr) else Writeln(_fa);
end;
end.[/pascal]

Posted: Wed Jun 26, 2002 2:29 pm
by Adrian Kuegel
If I understand your algorithm, you made the mistake here:
for i:=0 to L-Cars[j] do

try for i:=L-Cars[j] downto 0 do

Posted: Wed Jun 26, 2002 4:47 pm
by Revenger
I change my program, but it stil gets WA :(

[pascal]Program p10261;

Const MaxL = 100*100;
MaxC = 5000;
_tr = 'port';
_fa = 'starboard';

Var Inf : array[0..MaxL]of record ok,use : integer end;
Cars,Sum : array[0..MaxC]of integer;
Use : array[1..MaxC]of boolean;
i,j,L,N,ok,k : Integer;
T,TT : Integer;

begin
Read(T);
for TT:=1 to T do begin
if TT>1 then Writeln;
Read(L); L:=L*100; N:=0;
while true do begin
N:=N+1;
Read(Cars[N]);
if Cars[N]=0 then break;
end;
N:=N-1;
for i:=1 to MaxL do Inf.ok:=-1;
Inf[0].ok:=0; Inf[0].use:=0; Sum[0]:=0;
for j:=1 to N do begin
Sum[j]:=Sum[j-1]+Cars[j];
for i:=L-Cars[j] downto 0 do
if Inf.ok=0 then
if Inf[i+Cars[j]].ok=-1 then
if Sum[j]-i-Cars[j]<=L then begin
Inf[i+Cars[j]].ok:=0;
Inf[i+Cars[j]].use:=j;
ok:=1;
end;
end;
k:=0;
for i:=0 to L do
if Inf.ok=0 then
if Inf.use>Inf[k].use then
k:=i;
Writeln(Inf[k].use);
for i:=1 to Inf[k].use do Use:=false;
j:=k;
while true do begin
if j=0 then break;
Use[Inf[j].use]:=true;
j:=j-Cars[Inf[j].use];
end;
for i:=1 to Inf[k].use do
if Use then Writeln(_tr) else Writeln(_fa);
end;
end.[/pascal]

Posted: Wed Jun 26, 2002 6:01 pm
by Kamp
It's not a multiple input !!! :(

Just delete the first 3 lines after 'begin' and one 'end' at should be working :D

Also you should use 'readln' instead of 'read' :)

Good Luck !! :P

Posted: Wed Jun 26, 2002 6:09 pm
by Revenger
You are wrong. In problem says:
The Input
The input begins with a single positive integer on a line by itself indicating the number of the cases following, each of them as described below. This line is followed by a blank line, and there is also a blank line between two consecutive inputs.


The first line of input contains a single integer between 1 and 100: the length of the ferry (in metres). For each car in the queue there is an additional line of input specifying the length of the car (in cm, an integer between 100 and 3000 inclusive). A final line of input contains the integer 0. The cars must be loaded in order, subject to the constraint that the total length of cars on either side does not exceed the length of the ferry. Subject to this constraint as many cars should be loaded as possible, starting with the first car in the queue and loading cars in order until no more can be loaded.

Posted: Wed Jun 26, 2002 8:00 pm
by Kamp
Yes, you're right :oops:

My mistake...I read the old version of the problem description :(

Sorry :)

Posted: Wed Jun 26, 2002 8:38 pm
by Kamp
I've tested your program on several inputs, and for data:
1

6
200
200
400
400
your program gives:
3
port
starboard
port
If I correctly understand the problem, the output should be different :(

Posted: Thu Jun 27, 2002 11:32 am
by Revenger
Thank you, but it still get WA :oops:

[pascal]Program p10261;

Const MaxL = 100*100;
MaxC = 5000;
_tr = 'port';
_fa = 'starboard';

Var Inf : array[0..MaxL]of record ok,use : integer end;
Cars,Sum : array[0..MaxC]of integer;
Use : array[1..MaxC]of boolean;
i,j,L,N,ok,k : Integer;
T,TT : Integer;

begin
Read(T);
for TT:=1 to T do begin
if TT>1 then Writeln;
Read(L); L:=L*100; N:=0;
while true do begin
N:=N+1;
Read(Cars[N]);
if Cars[N]=0 then break;
end;
N:=N-1;
for i:=1 to MaxL do Inf.ok:=-1;
Inf[0].ok:=0; Inf[0].use:=0; Sum[0]:=0;
for j:=1 to N do begin
Sum[j]:=Sum[j-1]+Cars[j];
for i:=L-Cars[j] downto 0 do
if Inf.ok=0 then
if i+Cars[j]>=Sum[j]-i-Cars[j] then begin
Inf[i+Cars[j]].ok:=0;
Inf[i+Cars[j]].use:=j;
ok:=1;
end;
end;
k:=0;
for i:=0 to L do
if Inf.ok=0 then
if Inf.use>Inf[k].use then
k:=i;
Writeln(Inf[k].use);
for i:=1 to Inf[k].use do Use:=false;
j:=k;
while true do begin
if j=0 then break;
Use[Inf[j].use]:=true;
j:=j-Cars[Inf[j].use];
end;
for i:=1 to Inf[k].use do
if Use then Writeln(_tr) else Writeln(_fa);
end;
end.[/pascal]

Hmm..

Posted: Thu Jun 27, 2002 11:52 am
by cyfra
Hmm....

You would better check your program for the input in the task description...

Because you have wrong answer for this test case !!

So try to change it :wink:

Posted: Thu Jun 27, 2002 12:08 pm
by Revenger
Many thanks to all who helped me. Now I get Accepted 8) But my program use 31 MB of memory and run about 10 sec :(

Posted: Thu Jun 27, 2002 12:48 pm
by Revenger
Wow! Now it get Accepted in 1 second usung 8 MB of memory :lol:

Posted: Thu Jun 27, 2002 1:46 pm
by Kamp
Waw :D

Nice time :lol:

Congratulation :wink:

10261 Ferry Loading

Posted: Thu Aug 01, 2002 2:27 pm
by henar2
Hi all, I have sent the problem 10261 Ferry Loading and I am getting WA, could anyone send me or post here some inputs and outputs.
Thanks in advance.

Alfredo Guti

Posted: Wed Aug 07, 2002 4:43 pm
by Rivaldo
I also got WA. So i want to know whether i should keep abs(portlen - starboardlen) is minimal. Can anyone who got AC tell me that?

Posted: Sat Aug 17, 2002 12:59 pm
by obayashi
it's just a knap-sack like problem.
think it over and u will find what to do with this problem:)

good luck~