POJ2513Colored Sticks(欧拉路加字典树)
1 #include <cstdio> 2 #include <cstring> 3 #include <algorithm> 4 using namespace std; 5 const int maxn = 5e5 + 10; 6 const int maxsize = 27; 7 8 int par[maxn]; 9 int rnk[maxn]; 10 char s1[20], s2[20]; 11 int vis[maxn]; 12 int ch[maxn][maxsize]; 13 int val[maxn]; 14 15 int t; 16 17 void init() { 18 for (int i = 0; i < maxn; i++) { 19 par[i] = i; 20 rnk[i] = 0; 21 } 22 } 23 24 int find(int x) { 25 if (par[x] == x) return x; 26 else return par[x] = find(par[x]); 27 } 28 29 void unite(int x, int y) { 30 x = find(x); 31 y = find(y); 32 if (x == y) return; 33 34 if (rnk[x] < rnk[y]) { 35 par[x] = y; 36 } else { 37 par[y] = x; 38 if (rnk[x] == rnk[y]) rnk[x]++; 39 } 40 } 41 42 bool same(int x, int y) { 43 return find(x) == find(y); 44 } 45 46 struct Tire { 47 int sz; 48 Tire() { 49 sz = 1; 50 memset(ch[0], 0, sizeof(ch[0])); 51 } 52 int idx(char c) {return c - 'a';} 53 54 int FFF(char* s) { 55 int len = strlen(s); 56 int u = 0; 57 for (int i = 0; i < len; i++) { 58 int c = idx(s[i]); 59 if (!ch[u][c]) { 60 memset(ch[sz], 0, sizeof(ch[sz])); 61 val[sz] = 0; 62 ch[u][c] = sz++; 63 } 64 u = ch[u][c]; 65 } 66 if (!val[u]) val[u] = t++; 67 return val[u]; 68 } 69 70 }; 71 72 73 74 int main() { 75 init(); 76 int tag = 0; 77 Tire Tree; 78 t = 1; 79 while (~scanf("%s%s", s1, s2)) { 80 int a = Tree.FFF(s1), b = Tree.FFF(s2); 81 vis[a]++; vis[b]++; 82 if (!same(a, b)) { 83 unite(a, b); 84 } 85 tag++; 86 //if (tag == 5) break; 87 } 88 int odd = 0; 89 bool flag = 1; 90 for (int i = 1; i < t && flag; i++) { 91 if (vis[i] & 1) odd++; 92 if (find(i) != find(1)) flag = 0; 93 } 94 if (odd != 0 && odd != 2) { 95 flag = 0; 96 } 97 if (flag) { 98 puts("Possible"); 99 } else { 100 puts("Impossible"); 101 } 102 return 0; 103 }