欧拉回路三水题 POJ 1041 POJ 2230 POJ 1386

#include <cstdio>
#include <cstring>
#define maxn 2010
int map[50][maxn],degree[50];
int stack[maxn],top;
bool vis[maxn];
int m;

inline int max(int a,int b){
return a > b ? a : b;
}
void euler(int u){
for(int i = 1;i <= m;i++){
if(map[u][i] && !vis[i]){
vis[i] = 1;
euler(map[u][i]);
stack[top++] = i;
}
}
}

int main(){
int x,y,z;
while(scanf("%d%d",&x,&y)){
if(!x && !y)    break;
memset(map,0,sizeof(map));
memset(vis,0,sizeof(vis));
memset(degree,0,sizeof(degree));
top = m = 0;
scanf("%d",&z);
degree[x]++;degree[y]++;
map[x][z] = y;map[y][z] = x;
m = max(m,z);
while(scanf("%d%d",&x,&y)){
if(!x && !y)    break;
scanf("%d",&z);
degree[x]++;degree[y]++;
map[x][z] = y;map[y][z] = x;
m = max(m,z);
}
bool flag = false;
for(int i = 1;i < 50;i++){
if(degree[i]&1){
flag = true;
break;
}
}
if(flag){
printf("Round trip does not exist.\n");
continue;
}
euler(1);
for(int i = top-1;i >= 0;i--){
if(!flag){
printf("%d",stack[i]);
flag = true;
}
else    printf(" %d",stack[i]);
}
printf("\n");
}
return 0;
}