73 lines
2.1 KiB
C++
73 lines
2.1 KiB
C++
#include<iostream>
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#include<stdio.h>
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#include<string.h>
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#include<cmath>
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#include<queue>
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#include<stack>
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#include<set>
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#include<time.h>
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#include<map>
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#include<algorithm>
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#define ll long long
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#define eps 1e-5
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#define oo 1000000007
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#define pi acos(-1.0)
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#define MAXN 100005
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#define MAXM 500005
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using namespace std;
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int P[2][26],father[26];
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bool used[26];
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char s[1005];
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int getfather(int x)
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{
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if (father[x]==x) return x;
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return father[x]=getfather(father[x]);
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}
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int main()
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{
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int i,cases,n,m,x,y,t1,t2;
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scanf("%d",&cases);
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while (cases--)
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{
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scanf("%d",&n);
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memset(used,false,sizeof(used));
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memset(P,0,sizeof(P));
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for (i=0;i<26;i++) father[i]=i;
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for (i=1;i<=n;i++)
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{
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scanf("%s",s+1);
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x=s[1]-'a',y=s[strlen(s+1)]-'a';
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P[0][x]++,P[1][y]++;
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father[getfather(x)]=getfather(y);
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used[x]=used[y]=true;
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m=getfather(x);
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}
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if (n==1)
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{
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printf("Ordering is possible.\n");
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continue;
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}
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for (i=0;i<26;i++)
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if (used[i] && getfather(i)!=m) break;
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if (i<26)
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{
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printf("The door cannot be opened.\n");
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continue;
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}
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t1=t2=0;
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for (i=0;i<26;i++)
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{
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if (P[0][i]==P[1][i]) continue;
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if (P[0][i]+1==P[1][i]) t1++;
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else
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if (P[1][i]+1==P[0][i]) t2++;
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else break;
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}
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if (i<26 || !(t1==1 && t2==1 || !t1 && !t2))
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printf("The door cannot be opened.\n");
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else
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printf("Ordering is possible.\n");
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}
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return 0;
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}
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