OJ Board

i can't find out whats the wrong with my code! plz help me with that.
here's my code:-
.............................................................................................................
#include<stdio.h>
#include<math.h>
int x[100],a=0,b,rec[1000][10];
int place(int k, int i){
int j;
for(j=1;j<k;j++)
if((x[j]==i)||(labs(x[j]-i)==labs(j-k)))
return 0;
return 1;
}
void nqueens(int k, int n){
int i;
for(i=1;i<=n;i++){
if(place(k,i)){
x[k]=i;
if(k==n){ b=0;
for(i=1;i<=n;i++){
rec[a]=x;
b++;
}
a++;
}
else nqueens(k+1,n);
}
}
}
int main(){
// freopen("nQu.in","rt",stdin);
// freopen("nquee.out","w",stdout);
int k,n,i,r,c,j,gg,p[9],y,v;
nqueens(1,8);
while(scanf("%d%d",&r,&c)==2){
y=1;
printf("SOLN\t COLUMN\n");
printf(" #\t");
for(gg=1;gg<=8;gg++){
if(gg>1)printf(" ");
printf("%d",gg);
}
printf("\n\n");

for(i=0;i<a;i++) {
gg=0;
if(rec[r-1]==c){
printf(" %d\t",y);
y++;
for(j=0;j<b;j++){

if(gg>0) printf(" ");

printf("%d",rec[j]);
gg++; }
printf("\n");
}
}
}

return 0;
}

i can't find out whats the wrong with my code! plz help me with that.
here's my code:-
.............................................................................................................
#include<stdio.h>
#include<math.h>
int x[100],a=0,b,rec[1000][10];
int place(int k, int i){
int j;
for(j=1;j<k;j++)
if((x[j]==i)||(labs(x[j]-i)==labs(j-k)))
return 0;
return 1;
}
void nqueens(int k, int n){
int i;
for(i=1;i<=n;i++){
if(place(k,i)){
x[k]=i;
if(k==n){ b=0;
for(i=1;i<=n;i++){
rec[a]=x;
b++;
}
a++;
}
else nqueens(k+1,n);
}
}
}
int main(){
// freopen("nQu.in","rt",stdin);
// freopen("nquee.out","w",stdout);
int k,n,i,r,c,j,gg,p[9],y,v;
nqueens(1,;
while(scanf("%d%d",&r,&c)==2){
y=1;
printf("SOLN\t COLUMN\n");
printf(" #\t");
for(gg=1;gg<=8;gg++){
if(gg>1)printf(" ");
printf("%d",gg);
}
printf("\n\n");

for(i=0;i<a;i++) {
gg=0;
if(rec[r-1]==c){
printf(" %d\t",y);
y++;
for(j=0;j<b;j++){

if(gg>0) printf(" ");

printf("%d",rec[j]);
gg++; }
printf("\n");
}
}
}

return 0;
}

using spaces instead of tab ('\t') might help

I keep getting rejected, and the problem seems to be input:
I 've tried
cin>>R>>C;

and

scanf("%d%d", &R,&C);

but I keep getting 20 for R (i found this out using assert()), which doesn't make sense...

did you guys use any special tricks for input? Or is the input just wrong?
any help is appreciated.

Still I'm running into problems with input. I even tried this simple code:
[c]
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>

int main ()
{

int row;
int col;

if (scanf ("%d %d", &row, &col)!=2){
return 1;
}
if (row<1 || row>8 || col<1 ||col>8 ){
if (row==20){
assert(0);
}
}

return 0;
}


[/c]

And it gets Runtime Error, proving that it indeed reads 20 for row number.
I'm really confused now...
Does anyone have any idea why this happens?

-----------------------
ok, i've figured it out, it's "multiple input" format. It would be more helpful
to state the format inside the problem statement though. The sample input is especially misleading.

I've made some tests with the Online Judge for the problem 750 - "8 Queens Chess Problem" and i might supose that something is wrong in the inputs used for the judge to eval the problem.

The problem specifies Input to your program will be two numbers separated by a blank. The numbers represent the square on which one of the eight queens must be positioned. A valid square will be represented; it will not be necessary to validate the input.

And after study all the wrong answers i received from judge i reached the conclusion that one of the inputs has number 20 as one of the two numbers that forms the input line. The number 20 cannot be a valid number, only 1 to 8 should be allowed, so the executions always get wrong answer in this problem.

This is not a very difficult problem, but its rating is ridiculous (less than 10%), that's another fact that makes me believe something is not working in the jugdement...

Am I wrong? Or really the input is corrupted? I don't know if I must post this topic in this section or send a mail to any administrator of the Online Judge...

I will be waiting an answer, thank you very much!

Joan, SPAIN

Well, it's a multiple input problem... Probably, 20 is the number of test cases.

PS: For the description of multiple input format take a look here.

Good luck!

But in this problem it is not specified that a multiple input should be considered. It specifies that only two numbers are the input of the problem.

http://acm.uva.es/p/v7/750.html

Did you solve it allowing multiple input? Thanks!

There's a blue tick next to the problem's name on this page. It means multiple input.

I'll copy-paste the meanings of the colours:

The yellow colour means a special correction program for that problem; the blue colour means multiple input; finally, the green colour (a mix of blue and yellow) means a problem with multiple inputs and a special judge program.

Good luck!

You were right! Thank you very much for you help! I thought that all the problems with multiple input would be explained in the statement of each problem. Now I will check the color of the mark before implementing my solutions...

THanks again!

My code works for sample, but gets WA. I'm aware its multiple-input, and have coded for such.

[cpp]/*code removed*/[/cpp]

Any test cases would be appreciated. Thanks.

I solved this problem a few days ago. If you post some inputs and outputs of your executions, i will do the same with my file to check where might be the wrong answer...

Joan, SPAIN

I found my problem.
I got column/row mixed up in the input.
I have AC now.

I can't figure out what's wrong with my program:

on the input:

1
1 1

Note the first number is the number of cases(since is a multiple input problem as stated in the problemset)

i yields:

SOLN COLUMN
# 1 2 3 4 5 6 7 8

1 1 5 8 6 3 7 1 4 /*Here is the problem*/
2 1 6 8 3 7 4 2 5
3 1 7 4 6 8 2 5 3
4 1 7 5 8 2 4 6 3

when it should be:

SOLN COLUMN
# 1 2 3 4 5 6 7 8

1 1 5 8 6 3 7 2 4
2 1 6 8 3 7 4 2 5
3 1 7 4 6 8 2 5 3
4 1 7 5 8 2 4 6 3

even though when i print the board(//printBoard()//) to check it's correct
i can see the mistake
i would apreciate any help!!!

Here is my code:

[c]#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct {
int colum[8];
} SOLUCION;

SOLUCION sols[100];/*Array of sols*/

char board[8][8]; /*board*/
int nSols; /*Number of solutions*/

void printBoard() {
int i,j;
system("cls");
for(i=0;i<8;i++) {
for(j=0;j<8;j++) {
printf("%d ",board[j]);
}
printf("\n");
}
system("pause");

}

int compara(const void *a,const void *b) { /*func used in qsort*/
SOLUCION S1,S2;
int i;
S1 = *(SOLUCION *)a;
S2 = *(SOLUCION *)b;
for(i=0;i<8 && S1.colum==S2.colum;i++);
if(i==8) {
return 0;
}
else {
return(S1.colum-S2.colum);
}
}
/*To validate queens positon*/
int valid(int y,int x) {
int i,j;
int res=1;
/*VERTICAL*/
for(i=y;i>-1;i--) {
if(board[x]==1) {
res=0;
break;
}
}
for(i=y;i<8;i++) {
if(board[x]==1) {
res=0;
break;
}
}
/*DIAGONAL*/
for(i=y,j=x;i>-1 && j>-1;i--,j--) {
if(board[j]==1) {
res=0;
break;
}
}
for(i=y,j=x;i>-1 && j<8;i--,j++) {
if(board[j]==1) {
res=0;
break;
}
}
/**/
for(i=y,j=x;i<8 && j>-1;i++,j--) {
if(board[j]==1) {
res=0;
break;
}
}
for(i=y,j=x;i<8 && j<8;i++,j++) {
if(board[i][j]==1) {
res=0;
break;
}
}
return res;
}

/*SOLVER FUNCTION*/
void solve(int step,int row,int col) {
int i,k;
if(step==8) {
nSols++;
/*printBoard();*/
}
else {
if(step==row) {
sols[nSols].colum[col]=row;
solve(step+1,row,col);
}
else {
for(k=0;k<8;k++) {
if(valid(step,k)==1) {
board[step][k]=1;
sols[nSols].colum[k]=step;
solve(step+1,row,col);
board[step][k]=0;
}
}
}
}
}
/*END OF SOLVER*/

int main() {
int row,col;
int ncasos;
int i,j;

/* FILE *in;
in=fopen("8queens.in","r");*/
scanf("%d",&ncasos);
while(ncasos>0) {
ncasos--;
scanf("%d %d",&row,&col);
nSols=0;
memset(board,0,sizeof(int)*64);
memset(sols,0,sizeof(SOLUCION)*100);
printf("SOLN\t COLUMN\n");
printf(" #\t");
for(i=0;i<8;i++) {
printf("%d ",i+1);
}
printf("\n\n");
board[row-1][col-1]=1;
solve(0,row-1,col-1);
qsort(sols,nSols,sizeof(SOLUCION),compara);
for(i=0;i<nSols;i++) {
printf("%2d\t",i+1);
for(j=0;j<8;j++) {
printf("%d ",sols[i].colum[j]+1);
}
printf("\n");
}
printf("\n");
}
// fclose(in);
system("pause");
return 0;

}[/c]