> > #include <iostream>
> > using namespace std;
> >
> > struct stack {
> >  int data;
> >  stack* next;
> > };
> >
> > stack* m[1001];
> > int n,a;
> > stack *st,*ce;
> >
> > void push(stack* &s,int what) {
> > stack* tmp=new stack;
> >  if (tmp==NULL) { cout<<"Allocation Error"<<endl; return; }
> >  tmp->next=s;
> >  tmp->data=what;
> >  s=tmp;
> > }
> >
> > int pop(stack* &s) {
> > stack* tmp;
> > int q;
> >  if (s==NULL) { cout<<"Stack already empty"<<endl; return -1; }
> >  tmp=s;
> >  q=s->data;
> >  s=s->next;
> >  delete tmp;
> >  return q;
> > }
> >
> > int top(stack* s) {
> >  if (s==NULL) { cout<<"Stack empty"<<endl; return -1; } else
return
> s-
> > >data;
> > }
> >
> >
> > void init() {
> >  int p;
> >  cin>>n>>a;
> >  for (int i=1;i<=n;i++)
> >   for (int j=1;j<=n;j++) {
> >    cin>>p;
> >    p=!p;
> >    if(i==j) p=0;
> >    if (p) push(m[i],j);
> >   }
> > }
> >
> > int empty(stack* s) {
> >  if (s==NULL) return 1; else return 0;
> > }
> >
> > void solve() {
> >  push(st,a);
> >  while (st!=NULL) {
> >   int v=top(st);
> >   if (m[v]!=NULL) push(st,pop(m[v]));
> >    else push(ce,pop(st));
> >  }
> > }
> >
> > void print() {
> >  int prev=pop(ce);
> >  while(ce!=NULL) {
> >   cout<<prev<<" "<<top(ce)<<endl;
> >   prev=pop(ce);
> >  }
> > }
> >
> > int main() {
> >  st=NULL;
> >  ce=NULL;
> >  init();
> >  solve();
> >  print();
> >  return 0;
> > }

Well,
1. I know a person who got AC with exactly that :))
2. Finding an Euler Cycle in a graph is not a bad algorithm. It isO
(|E|) operations, where E is the quantity of the edges in the graph.
And if it is 32000, calculate how much time it takes :))) Certainly,
the algorithm (having in mind that even someone got AC with that ) is
not bad........................