填坑系列(p.172)
注意“可以旋转和翻转”
然后将每个字母看成点
不然边数就是n^2级的
1 #include<cstdio> 2 #include<cstring> 3 #include<cstdlib> 4 #include<algorithm> 5 #include<iostream> 6 7 using namespace std; 8 9 void setIO(const string& s) { 10 freopen((s + ".in").c_str(), "r", stdin); 11 freopen((s + ".out").c_str(), "w", stdout); 12 } 13 template<typename Q> Q read(Q& x) { 14 static char c, f; 15 for(f = 0; c = getchar(), !isdigit(c); ) if(c == '-') f = 1; 16 for(x = 0; isdigit(c); c = getchar()) x = x * 10 + c - '0'; 17 if(f) x = -x; 18 return x; 19 } 20 template<typename Q> Q read() { 21 static Q x; read(x); return x; 22 } 23 24 int ID(char a1, char a2) { 25 return (a1 - 'A') << 1 | (a2 == '-'); 26 } 27 28 int G[52][52]; 29 30 void AddEdge(char a1, char a2, char b1, char b2) { 31 if(a1 == '0' || b1 == '0') return; 32 int u = ID(a1, a2) ^ 1, v = ID(b1, b2); 33 G[u][v] = 1; 34 } 35 36 int vis[52]; 37 38 bool dfs(int u) { 39 vis[u] = -1; 40 for(int v = 0; v < 52; v++) if(G[u][v]) { 41 if(vis[v] < 0) return 1; 42 if(!vis[v] && dfs(v)) return 1; 43 } 44 vis[u] = 1; 45 return 0; 46 } 47 48 bool find() { 49 memset(vis, 0, sizeof vis); 50 for(int u = 0; u < 52; u++) if(!vis[u]) { 51 if(dfs(u)) return 1; 52 } 53 return 0; 54 } 55 56 int main() { 57 #ifdef DEBUG 58 freopen("in.txt", "r", stdin); 59 freopen("out.txt", "w", stdout); 60 #endif 61 62 int n; 63 while(scanf("%d", &n) == 1 && n) { 64 memset(G, 0, sizeof G); 65 char s[10]; 66 for(int i = 0; i < n; i++) { 67 scanf("%s", s); 68 for(int i = 0; i < 4; i++) { 69 for(int j = 0; j < 4; j++) if(i ^ j) { 70 AddEdge(s[i << 1], s[i << 1 | 1], s[j << 1] , s[j << 1 | 1]); 71 } 72 } 73 } 74 if(find()) puts("unbounded"); 75 else puts("bounded"); 76 } 77 78 return 0; 79 }