Poj 2513 connects the match dictionary tree + Euler's path

Colored Sticks
Time Limit: 5000 MS Memory Limit: 128000 K
Total Submissions: 27134 Accepted: 7186

Description

You are given a bunch of wooden sticks. each endpoint of each stick is colored with some color. is it possible to align the sticks in a straight line such that the colors of the endpoints that touch are of the same color?
Input

Input is a sequence of lines, each line contains two words, separated by spaces, giving the colors of the endpoints of one stick. A word is a sequence of lowercase letters no longer than 10 characters. there is no more than 250000 sticks.
Output

If the sticks can be aligned in the desired way, output a single line saying Possible, otherwise output Impossible.
Sample Input

Blue red
Red violet
Cyan blue
Blue magenta
Magenta cyan
Sample Output

PossibleHint

Huge input, scanf is recommended.
Source

The UofA Local 2000.10.14
 
Q: There are a lot of fireworks, each with the same color, that can be connected with another match and ask if these matches can be connected into a line.
 
Idea: obviously this is an issue with the Euler's path.
Mark the id of the string with the dictionary tree
Map timeout

#include<stdio.h>#include<string>#include<string.h>#include<map>#include<malloc.h>using namespace std;#define N 250000+10char s1[100],s2[100];int rank[N],fa[N],num[N],co=0;struct haha{    int id;    struct haha *next[26];}*root;struct haha * creat(){    int i;    struct haha *p;    p=(struct haha *)malloc(sizeof(struct haha));    p->id=-1;    for(i=0;i<26;i++) p->next[i]=NULL;    return p;};int update(char *s){     int d,pos,i;     struct haha *p;     p=root;d=strlen(s);     for(i=0;i<d;i++)     {         pos=s[i]-'a';         if(p->next[pos]==NULL)         {             p->next[pos]=creat();             p=p->next[pos];         }         else         {             p=p->next[pos];         }     }     if(p->id==-1)     p->id=co++;     return p->id;}int  find(int n){    return n==fa[n]?n:fa[n]=find(fa[n]);}void join(int a,int b){        if(rank[a]>rank[b])        {            fa[b]=a;            rank[a]+=rank[b];        }        else        {            fa[a]=b;            rank[b]+=rank[a];        }}int main(){    int i,j,k,cnt=0,a,b,rem;    for(i=0;i<N;i++)    {        rank[i]=1;fa[i]=i;    }    memset(num,0,sizeof(num));    root=creat();    while(scanf("%s %s",s1,s2)!=EOF)    {         a=update(s1);         b=update(s2);         num[a]++;num[b]++;         a=find(a);b=find(b);         if(a==b) continue;          join(a,b);    }    cnt=0;    int temp=find(0);    for(i=0;i<N;i++)    {        if(num[i]%2==1) cnt++;        if(cnt>2) {printf("Impossible\n");return 0;}        if(num[i]!=0&&find(i)!=temp) {printf("Impossible\n");return 0;}    }    printf("Possible\n");    return 0;}