/* >>~~ UVa Online Judge ACM Problem Solution ~~<< ID: 10001 Name: Garden of Eden Problem: https://onlinejudge.org/external/100/10001.pdf Language: C++ Author: Arash Shakery Email: arash.shakery@gmail.com */ #include #include using namespace std; #define isset(n,i) (((n)>>(i))&1) int automaton,n; bool nstate[40],bstate[40]; bool BT(int i) { if(i==n) { int t1=4*bstate[n-2] + 2*bstate[n-1] + bstate[0]; int t2=4*bstate[n-1] + 2*bstate[0] + bstate[1]; if(nstate[n-1] == isset(automaton,t1) && nstate[0]==isset(automaton,t2)) return true; else return false; } bool ans=false; int t1=4*bstate[i-2] + 2*bstate[i-1] + 1; if(isset(automaton,t1) == nstate[i-1]) { bstate[i]=1; ans|= BT(i+1); } int t2=4*bstate[i-2] + 2*bstate[i-1] + 0; if(isset(automaton,t2) == nstate[i-1]) { bstate[i]=0; ans|= BT(i+1); } return ans; } bool answer() { int i; for(i=0; i<8; i++) if( isset(automaton,i) == nstate[1] ) { bstate[0]= isset(i,2); bstate[1]= isset(i,1); bstate[2]= isset(i,0); if(BT(3)) return true; } return false; } int main() { char s[40]; int i; while(cin>>automaton>>n>>s) { for(i=0; s[i]; i++) if(s[i]=='1') nstate[i]=1; else nstate[i]=0; if(answer()) puts("REACHABLE"); else puts("GARDEN OF EDEN"); } }