POJ 2513 Colored Sticks(Trie+并查集+欧拉回路)

//TRIE + 并查集 +　欧拉回路//A了这道题，学会了用并查集判断无向图的连通性#include<iostream>#include<map>#include<string>using namespace std;const int MAX = 500003;int N;int fa[MAX];int deg[MAX];struct trie{int color;trie *next[26];trie(){color = 0;memset(next,0,sizeof(next));}}*root;int insert(trie *p,char str[]){for(int i = 0;i < strlen(str);++i){int s = str[i] - 'a';if(p->next[s] == NULL)p->next[s] = new trie;p = p->next[s];if(i == strlen(str) - 1){if(p->color == 0)p->color = ++N;++deg[p->color];return p->color;}}}void init(){for(int i = 1;i <= MAX;++i)fa[i] = i;}int Find(int x){if(x == fa[x])return x;else return fa[x] = Find(fa[x]);}void Union(int x,int y){x = Find(x);y = Find(y);fa[x] = y;}bool isConnected(){for(int i = 2;i <= N;++i)if(Find(i) != Find(i-1))return false;return true;}int main(){//freopen("in.txt","r",stdin);char c1[11],c2[11];bool ok = 1;int x,y,oddDeg = 0;N = 0;root = new trie;memset(deg,0,sizeof(deg));init();while(scanf("%s%s",c1,c2) != EOF){x = insert(root,c1);y = insert(root,c2);Union(x,y);}if(!isConnected()){printf("Impossible/n");return 0;}for(int i = 1;i <= N;++i){if(deg[i] % 2 != 0)++oddDeg;if(oddDeg > 2){printf("Impossible/n");return 0;}}printf("Possible/n");return 0;}