http://poj.org/problem?id=2513
每个单词为一个节点 并查集判联通 度数为偶数或有两个为奇数 4A 第三次是由于有多余的测试输出没删掉 前两次统计多少个单词 统计错了
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1 #include <iostream> 2 #include<cstdio> 3 #include<string.h> 4 using namespace std; 5 char s[500011][11]; 6 int dd,father[500011],r[500011],dk[500011]; 7 struct node 8 { 9 int de,da; 10 node *next[27]; 11 node() 12 { 13 de = 0; 14 da = 0; 15 memset(next,0,sizeof(next)); 16 } 17 }; 18 int find(int x) 19 { 20 if(x!=father[x]) 21 father[x] = find(father[x]); 22 return father[x]; 23 } 24 void ctree(node *t,char *c,int j) 25 { 26 int i,d,k = strlen(c); 27 node *p = t; 28 for(i = 0 ; i < k ; i++) 29 { 30 d = c[i]-'a'; 31 if(p->next[d]==NULL) 32 p->next[d] = new node; 33 p = p->next[d]; 34 } 35 p->de++; 36 if(p->da==0) 37 { 38 dd++; 39 p->da = dd; 40 } 41 r[j] = p->da; 42 dk[p->da] = p->de; 43 } 44 int main() 45 { 46 int i = 0,j,k,n,m; 47 dd = 0; 48 node *t = new node; 49 for(j = 1; j <= 500010 ; j++) 50 father[j] = j; 51 while(scanf("%s %s",s[i],s[i+1])!=EOF) 52 { 53 /*if(s[i][0]=='#') 54 break;*/ 55 ctree(t,s[i],i); 56 ctree(t,s[i+1],i+1); 57 int px = find(r[i]); 58 int py = find(r[i+1]); 59 if(px!=py) 60 father[px] = py; 61 i+=2; 62 } 63 int num = 0; 64 for(j = 1 ;j <= dd ; j++) 65 if(father[j]==j) 66 { 67 num++; 68 if(num>1) 69 break; 70 } 71 if(num>1) 72 printf("Impossible\n"); 73 else 74 { 75 num = 0; 76 for(j = 1 ; j <= dd ; j++) 77 { 78 if(dk[j]%2!=0) 79 num++; 80 } 81 if(num==2||num == 0) 82 printf("Possible\n"); 83 else 84 printf("Impossible\n"); 85 } 86 return 0; 87 }