POJ 2513

来源：互联网发布：晋业通软件怎样使用编辑：程序博客网时间：2024/05/16 11:57

并查集Union-Set：使用rank数组

Trie树

欧拉图

#include <iostream>const int MAXN = 500003;int N;int pre[MAXN];int rank[MAXN];int deg[MAXN];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 < (int)strlen(str); i++){int s = str[i] - 'a';if(p->next[s] == NULL)p->next[s] = new trie;p = p->next[s];if(i == (int)strlen(str) - 1){if(p->color == 0)p->color = ++N;++deg[p->color];return p->color;}}return 0;}void init(){for(int i = 1; i < MAXN; i++){pre[i] = i;rank[i] = 0;}}int find(int x){if(x != pre[x])pre[x] = find(pre[x]);return pre[x];}void unionOp(int x, int y){if(rank[x] < rank[y])pre[x] = pre[y];else if(rank[x] > rank[y])pre[y] = pre[x];else{pre[y] = pre[x];rank[x]++;}}bool isConnected(){for(int i = 2; i <= N; i++)if(find(i) != find(i - 1))return false;return true;}int main(){char c1[11], c2[11];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);unionOp(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;}