#include <iostream> #include <vector> using namespace std; using LL = long long; const int MOD = 1000000007; int main() { int n; cin >> n; vector<int> a(n); for (int i = 0; i < n; ++i) { cin >> a[i]; } int sum = 0; bool ok = true; for (int i = 0; i < n; ++i) { sum += a[i]; if (sum >= MOD) { ok = false; break; } } if (ok) { int cnt = 0; int sum = 0; for (int i = 0; i < n; ++i) { sum += a[i]; if (sum % 2 == 0) ++cnt; } int res = 0; if (sum % 2 == 0) { res = 1; for (int i = 1; i < cnt; ++i) { res = (res * 2) % MOD; } } cout << res << endl; } else { vector<int> dp(n + 1); dp[0] = 1; for (int i = 0; i < n; ++i) { LL rem = 0; for (int j = i; j >= 0; --j) { rem = (rem + a[j]) % MOD; if (rem % 2 == 0) dp[i + 1] = (dp[i + 1] + dp[j]) % MOD; } } cout << dp[n] << 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 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 | #include <iostream> #include <vector> using namespace std; using LL = long long; const int MOD = 1000000007; int main() { int n; cin >> n; vector<int> a(n); for (int i = 0; i < n; ++i) { cin >> a[i]; } int sum = 0; bool ok = true; for (int i = 0; i < n; ++i) { sum += a[i]; if (sum >= MOD) { ok = false; break; } } if (ok) { int cnt = 0; int sum = 0; for (int i = 0; i < n; ++i) { sum += a[i]; if (sum % 2 == 0) ++cnt; } int res = 0; if (sum % 2 == 0) { res = 1; for (int i = 1; i < cnt; ++i) { res = (res * 2) % MOD; } } cout << res << endl; } else { vector<int> dp(n + 1); dp[0] = 1; for (int i = 0; i < n; ++i) { LL rem = 0; for (int j = i; j >= 0; --j) { rem = (rem + a[j]) % MOD; if (rem % 2 == 0) dp[i + 1] = (dp[i + 1] + dp[j]) % MOD; } } cout << dp[n] << endl; } return 0; } |