#include <iostream> using namespace std; const int P=1000000007; int main() { ios_base::sync_with_stdio(false); int n; cin>>n; bool np=false; int wyn=-1; for (int i=0; i<n; ++i) { int a; cin>>a; if (a%2) np=!np; if (np) continue; if (wyn==-1) wyn=1; else { wyn*=2; if (P<=wyn) wyn-=P; } } cout<<(np ? 0 : wyn)<<endl; return 0; }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 | #include <iostream> using namespace std; const int P=1000000007; int main() { ios_base::sync_with_stdio(false); int n; cin>>n; bool np=false; int wyn=-1; for (int i=0; i<n; ++i) { int a; cin>>a; if (a%2) np=!np; if (np) continue; if (wyn==-1) wyn=1; else { wyn*=2; if (P<=wyn) wyn-=P; } } cout<<(np ? 0 : wyn)<<endl; return 0; } |