[U]3.3.1 歐拉迴路

歐拉迴路，採用遞迴的方法。採用遞迴的方法實現。

/*ID:bysenLANG:C++PROG:fence*/#include<stdio.h>#include<stack>#define MAXN 501#define MAXF 1025using namespace std;int map[MAXN][MAXN]={0};int circuit[MAXF];int nodenum;int maxnode=0;int degree[MAXN]={0};int N;int max( int a,int b ){ return a>b?a:b; }void work(int start){  bool found=false;  for( int i=1;i<=maxnode;i++ )  {    if( map[start][i] )    {     map[start][i]--;     map[i][start]--;     work(i);     found=true;   } } circuit[nodenum++]=start;}int main(){ freopen( "fence.in","r",stdin ); freopen( "fence.out","w",stdout ); scanf( "%d",&N ); for( int i=1;i<=N;i++ ) {  int u,v;  scanf( "%d %d",&u,&v );  maxnode=max(maxnode,u);  maxnode=max(maxnode,v);  degree[u]++;  degree[v]++;  map[u][v]++; map[v][u]++;}int start;for( int i=1;i<=maxnode;i++ ) if( degree[i]%2==1 ) {  start=i;  break; }    degree[start]--;work(start);for( int i=nodenum-1;i>=0;i-- ) printf( "%d\n",circuit[i] ); return 0;}