POJ - 2513 Colored Sticks

来源：互联网发布：淘宝商品数据包编辑：程序博客网时间：2024/05/21 07:08

题意：有一些木棍，木棍的两边各有一种颜色，如果两根木棍的一边颜色相同的话，那么就可以连在一起，问能不能完全连成一根

思路：不在是简单的欧拉路，如果能将颜色表达成一个数字的话就能转化为欧拉路了，

用Trie树来优化，再用并查集判断是否为欧拉路，将pre[]初始化为-1，加快速度

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <map>using namespace std;const int N = 15;const int M = 1000010;struct Trie{    int num;    Trie *next[26];}*Head;Trie trie[M];char u[N],v[N];int num,n,top,total,flag;int pre[M],in[M];int Find_set(int x){    return pre[x] == -1 ? x : (pre[x] = Find_set(pre[x]));}void Make_Set(int x,int y){    int root1 = Find_set(x);    int root2 = Find_set(y);    if (root1 != root2)        pre[root2] = root1;}int insert(char *str){    Head = &trie[0];    int len = strlen(str);    for (int i = 0; i < len; i++){        int temp = str[i] - 'a';        if (Head->next[temp] == NULL)            Head->next[temp] = &trie[++num];        Head = Head->next[temp];    }    if (Head->num == 0)        Head->num = top++;    return Head->num;}void init(){    num = total = 0,top = 1,flag = 1;    memset(in,0,sizeof(in));    memset(pre,-1,sizeof(pre));    for (int i = 0; i < 20; i++){        trie[i].num = 0;        for (int j = 0; j < 26; j++)            trie[i].next[j] = NULL;    }}int main(){    int tmp,temp;    init();    while (scanf("%s %s",u,v) != EOF){        tmp = insert(u),temp = insert(v);        in[tmp]++,in[temp]++;        Make_Set(tmp,temp);    }    int root = Find_set(1);    for (int i = 1; i < top; i++){        if (root != Find_set(i)){            flag = 0;            break;        }        if (in[i] & 1)            total++;        if (total > 2)            break;    }    if ((total == 0 || total == 2) && flag == 1)        printf("Possible\n");    else printf("Impossible\n");    return 0;}

0 0