POJ 2513 Colored Sticks <trie+并查集+欧拉路径>

题目：传送门。

分析：我好懒，直接分享一篇题解吧，传送门。

代码：#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
#include <cmath>
using namespace std;

const int MAXN=25e4+5;
class trieTree{
public:
int id;
trieTree *next[27];
trieTree(){
id=-1;
memset(next,0,sizeof next);
}
};
trieTree root;
int degree[MAXN*2];
int ancestor[MAXN*2];
int color;

int getID(char *str){
trieTree *t=&root;
for(int i=0;str[i]!='\0';++i){
int index=str[i]-'a';
if(!t->next[index]){
trieTree *tt=new trieTree;
t->next[index]=tt;
}
t=t->next[index];
}
return t->id>=0 ? t->id:t->id=color++;
}

int find(int x){
if(ancestor[x]!=x){
ancestor[x]=find(ancestor[x]);
}
return ancestor[x];
}

void unionSet(int x,int y){
int px=find(x),py=find(y);
ancestor[py]=px;
}

int main(){
color=0;
memset(degree,0,sizeof degree);
for(int i=0;i<MAXN*2;++i) ancestor[i]=i;
char c1[12],c2[12];
while(cin>>c1>>c2){
int x=getID(c1),y=getID(c2);
unionSet(x,y);
degree[x]++; degree[y]++;
}
int r=find(1),sum=0;
for(int i=0;i<color;++i){
if(degree[i]&1) sum++;
if(find(i)!=r){
cout<<"Impossible\n";
retur
4000
n 0;
}
if(sum>2){
cout<<"Impossible\n";
return 0;
}
}
if(sum==1) cout<<"Impossible\n";
else cout<<"Possible\n";
return 0;
}