#include <bits/stdc++.h>
#define ll long long
#define str string
#define pii pair<int, int>
#define pll pair<ll, ll>
#define fi first
#define se second
#define vc vector<char>
#define vvc vector<vc>
#define vi vector<int>
#define vvi vector<vi>
#define vvvi vector<vvi>
#define vvvvi vector<vvvi>
#define vll vector<ll>
#define vvll vector<vll>
#define vvvll vector<vvll>
#define vvvvll vector<vvvll>
#define vs vector<str>
#define vvs vector<vs>
#define vpii vector<pii>
#define vvpii vector<vpii>
#define vpll vector<pll>
#define vvpll vector<vpll>
#define vb vector<bool>
#define vvb vector<vb>
#define rep(i, a, b) for (int i = (a); i < int(b); i++)
#define repi(i, a, b) for (int i = (a); i <= int(b); i++)
using namespace std;
#define ui unsigned int
void solve() {
ll n; cin >> n;
vll A(n);
ll sum = 0;
ll MOD = 1000000000 + 7;
rep(i, 0, n) {
cin >> A[i];
sum += (ll)A[i];
}
if (sum < MOD) {
ll sumdp[2] = {1, 0};
vll dp(n + 1, 0);
dp[0] = 1;
rep(i, 0, n) {
if (A[i] % 2 == 1) {
swap(sumdp[0], sumdp[1]);
}
dp[i + 1] = sumdp[0];
sumdp[0] = (sumdp[0] + dp[i + 1]) % MOD;
}
cout << dp[n] << '\n';
}
else {
vll dp(n + 1, 0);
dp[0] = 1;
for (int i = 0; i < n; i++) {
ll sm = 0;
for (int j = i; j >= 0; j--) {
sm += A[j];
if ((sm % MOD) % 2 == 0) {
dp[i + 1] = (dp[i + 1] + dp[j]) % MOD;
}
}
}
cout << dp[n] << '\n';
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
bool _multipleTestCases = false;
if (_multipleTestCases) {
ll t; cin >> t;
while (t--)
solve();
}
else {
solve();
}
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 86 87 88 89 90 91 92 93 94 95 96 | #include <bits/stdc++.h> #define ll long long #define str string #define pii pair<int, int> #define pll pair<ll, ll> #define fi first #define se second #define vc vector<char> #define vvc vector<vc> #define vi vector<int> #define vvi vector<vi> #define vvvi vector<vvi> #define vvvvi vector<vvvi> #define vll vector<ll> #define vvll vector<vll> #define vvvll vector<vvll> #define vvvvll vector<vvvll> #define vs vector<str> #define vvs vector<vs> #define vpii vector<pii> #define vvpii vector<vpii> #define vpll vector<pll> #define vvpll vector<vpll> #define vb vector<bool> #define vvb vector<vb> #define rep(i, a, b) for (int i = (a); i < int(b); i++) #define repi(i, a, b) for (int i = (a); i <= int(b); i++) using namespace std; #define ui unsigned int void solve() { ll n; cin >> n; vll A(n); ll sum = 0; ll MOD = 1000000000 + 7; rep(i, 0, n) { cin >> A[i]; sum += (ll)A[i]; } if (sum < MOD) { ll sumdp[2] = {1, 0}; vll dp(n + 1, 0); dp[0] = 1; rep(i, 0, n) { if (A[i] % 2 == 1) { swap(sumdp[0], sumdp[1]); } dp[i + 1] = sumdp[0]; sumdp[0] = (sumdp[0] + dp[i + 1]) % MOD; } cout << dp[n] << '\n'; } else { vll dp(n + 1, 0); dp[0] = 1; for (int i = 0; i < n; i++) { ll sm = 0; for (int j = i; j >= 0; j--) { sm += A[j]; if ((sm % MOD) % 2 == 0) { dp[i + 1] = (dp[i + 1] + dp[j]) % MOD; } } } cout << dp[n] << '\n'; } } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); bool _multipleTestCases = false; if (_multipleTestCases) { ll t; cin >> t; while (t--) solve(); } else { solve(); } return 0; } |
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