UVa 10129 Play on Words 欧拉通路

来源：互联网发布：java 垃圾评论过滤编辑：程序博客网时间：2024/06/05 18:24
注意到给出的所有点可能不连通，所以要用并查集
#include<cstdio>#include<string>#include<cstring>#include<iostream>#include<cmath>#include<algorithm>#include<climits>#include<queue>#include<vector>#include<map>#include<sstream>#include<set>#include<stack>#include<utility>#pragma comment(linker, "/STACK:102400000,102400000")#define PI 3.1415926535897932384626#define eps 1e-10#define sqr(x) ((x)*(x))#define FOR0(i,n)  for(int i=0 ;i<(n) ;i++)#define FOR1(i,n)  for(int i=1 ;i<=(n) ;i++)#define FORD(i,n)  for(int i=(n) ;i>=0 ;i--)#define  lson   num<<1,le,mid#define rson    num<<1|1,mid+1,ri#define MID   int mid=(le+ri)>>1#define zero(x)((x>0? x:-x)<1e-15)using namespace std;const int INF =0x3f3f3f3f;const int maxn=  100000+20  ;//const int maxm=    ;//const int INF=    ;typedef long long ll;const ll inf =1000000000000000;//1e15;//ifstream fin("input.txt");//ofstream fout("output.txt");//fin.close();//fout.close();//freopen("a.in","r",stdin);//freopen("a.out","w",stdout);char s[1010];int in[maxn];int out[maxn];int pre[30];vector <int>spe;int id(char x){    return x-'a';}int find(int x){    return x==pre[x]?x:pre[x]=find(pre[x]);}void merge(int u ,int v){    int x=find(u);    int y=find(v);    if(x!=y)    pre[u]=v;}void init(){    for(int i=0;i<26;i++)        pre[i]=i;}int main(){    int T,n;    scanf("%d",&T);    while(T--)    {        spe.clear();        init();        for(int i=0;i<26;i++)        {            in[i]=out[i]=0;        }        scanf("%d",&n);        while(n--)        {            scanf("%s",s);            int len=strlen(s);            int st=id(s[0]);            int ed=id(s[len-1]);            merge( st,ed );            out[st]++;            in[ed]++;        }        for(int i=0;i<26;i++)        {            if(out[i]!=in[i])            spe.push_back(i);        }        int prin;        for(int i=0;i<26;i++)        {            if(in[i]!=0||out[i]!=0)            {prin=find(i);break;}        }        bool ok=1;        for(int i=0;i<26;i++)        {             if( (in[i]!=0||out[i]!=0 )&&find(i)!=prin )             {                 ok=0;                 break;             }        }        if(!ok)  { puts("The door cannot be opened.");continue;}        if(spe.size()==0)  {puts("Ordering is possible.");continue;}        else if(spe.size()==2)        {            int a=spe[0],b=spe[1];            if( in[a]-out[a]==1&&out[b]-in[b]==1||in[a]-out[a]==-1&&out[b]-in[b]==-1)                 {puts("Ordering is possible.");continue;}        }        puts("The door cannot be opened.");    }    return 0;}
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