#include <bits/stdc++.h> using namespace std; #define fo(i, n) for(int i=0; i<n; i++) #define FO(i, k, n) for(int i=k;i<n;i++) #define chck(x) cout<<#x<<" "<<x<<"\n"; template<typename... T> void read(T&... args){ ((cin >> args), ...); } #define ll long long const ll MOD = 1e9+7; const int MAX = 3e5+7; ll in[MAX]; int main(){ int n; cin >> n; FO(i, 1, n+1) cin >> in[i]; int a = 1, b = 1, sum = 0, pos = 0; while(a <= n){ do{ sum+=in[b]; b++; }while((sum%MOD)%2 != 0 and b <= n); if((sum%MOD)%2 == 0){ pos++; } else { cout << 0 << "\n"; return 0;} a = b; sum = 0; } ll w = 1; for(int i = 2; i <= pos; i++) w = (w * 2)%MOD; cout << w << "\n"; }
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 39 40 41 42 43 44 | #include <bits/stdc++.h> using namespace std; #define fo(i, n) for(int i=0; i<n; i++) #define FO(i, k, n) for(int i=k;i<n;i++) #define chck(x) cout<<#x<<" "<<x<<"\n"; template<typename... T> void read(T&... args){ ((cin >> args), ...); } #define ll long long const ll MOD = 1e9+7; const int MAX = 3e5+7; ll in[MAX]; int main(){ int n; cin >> n; FO(i, 1, n+1) cin >> in[i]; int a = 1, b = 1, sum = 0, pos = 0; while(a <= n){ do{ sum+=in[b]; b++; }while((sum%MOD)%2 != 0 and b <= n); if((sum%MOD)%2 == 0){ pos++; } else { cout << 0 << "\n"; return 0;} a = b; sum = 0; } ll w = 1; for(int i = 2; i <= pos; i++) w = (w * 2)%MOD; cout << w << "\n"; } |