11349 - Symmetric Matrix

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sharath
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Joined: Tue Sep 16, 2008 9:21 pm

Re: 11349 - Symmetric Matrix

Surprisingly executing the same code in my windows XP PC gives the proper output and I think it is because of fflush(stdin) statement which is platform dependent. So for the platforms not supporting fflush (stdin) the input logic fails and hence the code. Thanks for pointing it out, I changed the input logic and got AC
mf
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Re: 11349 - Symmetric Matrix

fflush(stdin) is a no-op in every sane programming environment, because fflush is only supposed to flush stream's *output* buffers.

But Microsoft's runtime library went totally nuts and defines it as discarding stream's input buffer as well. Well, usually it is a mistake to want to discard input buffers – or you'll risk throwing away the stuff you care about. Remember that the judge gives you the whole input at once from a file. Nobody's sitting there and typing the input line-by-line, as you might do in your own environment.
r2ro
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Re: 11349 - Symmetric Matrix

This problem is not difficult, but I cannot seem to get ACC. (WA always).

Here's my code, kindly check it out?

Code: Select all

Accepted. I was forgetting the '.' at the end xD
plamplam
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Posts: 150
Joined: Fri May 06, 2011 11:37 am

Re: 11349 - Symmetric Matrix

Ahh....very tricky and very nice The range of the integers are 2^32 <= Mij <= 2^32, so you must use long long int. I got Wrong Answer twice because of this . And remember to include a '.' at the end of all your results. Also remember that if any of the numbers is negative, then the matrix is non-symmetrical. For example:

Code: Select all

1
N = 3
-5 -1 -3
-2 0 -2
-3 -1 -5
The result for this one is non-symmetrical.
You tried your best and you failed miserably. The lesson is 'never try'. -Homer Simpson
shuvokr
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Re: 11349 - Symmetric Matrix

Remove after AC

Code: Select all

enjoying life .....
brianfry713
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Location: San Jose, CA, USA

Re: 11349 - Symmetric Matrix

Input:

Code: Select all

1
n = 1
-1
Correct output:

Code: Select all

Test #1: Non-symmetric.
Check input and AC output for thousands of problems on uDebug!
ahmed mohamed said
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Joined: Mon Apr 22, 2013 1:22 am

11349 - Symmetric Matrix why WA

#include <iostream>
using namespace std;
int main()
{
bool x = true;
int testcases;
cin>>testcases;
for(int t=1 ; t<=testcases; t++)
{
char Nu , eq ;
int N ;
cin>>Nu; cin>>eq ;cin>>N;
long** matrix = new long*[N];
for(int k = 0 ; k<N; k++)
matrix[k] = new long[N];
for(int i=0 ; i<N ; i++)
{
for (int j=0 ; j<N ; j++)
{
cin>>matrix[j];
}
}
for(int i=0 ; i<N ; i++)
{
for(int j=0 ; j<N ; j++)
{
if (matrix[j] < 0 )
{
x =false ;
break;
}
}
if(x == false)
break;
}
if (x==false)
{
cout<<"Test #"<<t<<": Non-symmetric."<<endl;
}
else
{

for(int i=0 ; i<N ; i++)
{
for(int j=0 ; j<N; j++)
{
if(matrix[j] == matrix[N-(i+1)][N-(j+1)])
x=true;
else
{
x=false;
break;
}
}
if(x == false)
break;
}
if(x)
cout<<"Test #"<<t<<": Symmetric."<<endl;
else
cout<<"Test #"<<t<<": Non-symmetric."<<endl;
}
for(int i=0 ; i<N ; i++)
delete []matrix;
delete []matrix;
}
return 0;
}
brianfry713
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Location: San Jose, CA, USA

Re: 11349 - Symmetric Matrix why WA

Use long long.
Check input and AC output for thousands of problems on uDebug!
uDebug
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Joined: Tue Jul 24, 2012 4:23 pm

Re: 11349 - Symmetric Matrix

Here's some input I found useful during testing / debugging.

Input:

Code: Select all

8
N = 3
5 1 3
2 -5 2
3 1 5
N = 4
4294967296 87 1 3
2 88 2 21
21 2 88 2
3 1 87 4294967296
N = 1
-1
N = 1
66
N = 2
4 5
5 4
N = 5
5 1 3 2 99
2 5 2 1 2
987 77 66 78 987
2 1 2 5 2
99 2 3 1 5
N = 5
5 1 3 2 99
2 5 2 1 2
987 77 66 77 987
2 1 2 5 2
99 2 3 1 5
N = 5
5 1 3 2 99
2 5 2 1 2
987 77 -66 78 987
2 1 2 5 2
99 2 3 1 5
AC Output:

Code: Select all

Test #1: Non-symmetric.
Test #2: Symmetric.
Test #3: Non-symmetric.
Test #4: Symmetric.
Test #5: Symmetric.
Test #6: Non-symmetric.
Test #7: Symmetric.
Test #8: Non-symmetric.
Check input and AC output for over 7,500 problems on uDebug!

jokerz
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Joined: Tue Nov 05, 2013 10:24 am

Re: 11349 - Symmetric Matrix

@ v1n1t
why case 6 is non-symmetric???
jokerz
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Posts: 8
Joined: Tue Nov 05, 2013 10:24 am

Re: 11349 - Symmetric Matrix

v1n1t wrote:Here's some input I found useful during testing / debugging.

Input:

Code: Select all

8
N = 3
5 1 3
2 -5 2
3 1 5
N = 4
4294967296 87 1 3
2 88 2 21
21 2 88 2
3 1 87 4294967296
N = 1
-1
N = 1
66
N = 2
4 5
5 4
N = 5
5 1 3 2 99
2 5 2 1 2
987 77 66 78 987
2 1 2 5 2
99 2 3 1 5
N = 5
5 1 3 2 99
2 5 2 1 2
987 77 66 77 987
2 1 2 5 2
99 2 3 1 5
N = 5
5 1 3 2 99
2 5 2 1 2
987 77 -66 78 987
2 1 2 5 2
99 2 3 1 5
AC Output:

Code: Select all

Test #1: Non-symmetric.
Test #2: Symmetric.
Test #3: Non-symmetric.
Test #4: Symmetric.
Test #5: Symmetric.
Test #6: Non-symmetric.
Test #7: Symmetric.
Test #8: Non-symmetric.
why case 6 is non symmetric???
brianfry713
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Location: San Jose, CA, USA

Re: 11349 - Symmetric Matrix

In the third row 77 != 78
Check input and AC output for thousands of problems on uDebug!
uDebug
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Joined: Tue Jul 24, 2012 4:23 pm

Re: 11349 - Symmetric Matrix

jokerz wrote:why case 6 is non symmetric???
brianfry713 wrote:In the third row 77 != 78
Thank you for helping make things clear.
Check input and AC output for over 7,500 problems on uDebug!