#include <bits/stdc++.h>
using namespace std;
const int N = 1e6 + 5;
#define st first
#define nd second
typedef pair<int,int> pun;
typedef long long ll;
ll mod = 1000 * 1000 * 1000 + 7;
void n2(vector<int> v, vector<ll> pref) {
vector<ll> dp;
dp.resize(v.size());
dp[0] = 1;
for (int i = 1; i < pref.size(); i ++) {
for (int j = 0; j < i; j ++) {
if (((pref[i] - pref[j]) % mod) % 2 == 0) {
dp[i] += dp[j];
}
}
dp[i] %= mod;
}
cout << dp[v.size() - 1];
}
void heura(vector<int> v, vector<ll> pref) {
vector<ll> dp;
dp.resize(v.size());
dp[0] = 1;
ll p = 1;
ll np = 0;
for (int i = 1; i < pref.size(); i ++) {
if (pref[i] % 2) {
dp[i] = np;
np += dp[i];
np %= mod;
} else {
dp[i] = p;
p += dp[i];
p %= mod;
}
}
cout << dp[v.size() - 1];
}
int main() {
ios_base::sync_with_stdio(false);
int n;
cin >> n;
vector<int> v;
v.push_back(0);
for (int i = 0; i < n; i ++) {
int x;
cin >> x;
v.push_back(x);
}
vector<ll> pref;
pref.push_back(0);
for (int i = 1; i <= n; i ++) {
pref.push_back(pref.back() + v[i]);
}
if (pref.back() < mod) {
heura(v, pref);
}
else n2(v, pref);
}
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 | #include <bits/stdc++.h> using namespace std; const int N = 1e6 + 5; #define st first #define nd second typedef pair<int,int> pun; typedef long long ll; ll mod = 1000 * 1000 * 1000 + 7; void n2(vector<int> v, vector<ll> pref) { vector<ll> dp; dp.resize(v.size()); dp[0] = 1; for (int i = 1; i < pref.size(); i ++) { for (int j = 0; j < i; j ++) { if (((pref[i] - pref[j]) % mod) % 2 == 0) { dp[i] += dp[j]; } } dp[i] %= mod; } cout << dp[v.size() - 1]; } void heura(vector<int> v, vector<ll> pref) { vector<ll> dp; dp.resize(v.size()); dp[0] = 1; ll p = 1; ll np = 0; for (int i = 1; i < pref.size(); i ++) { if (pref[i] % 2) { dp[i] = np; np += dp[i]; np %= mod; } else { dp[i] = p; p += dp[i]; p %= mod; } } cout << dp[v.size() - 1]; } int main() { ios_base::sync_with_stdio(false); int n; cin >> n; vector<int> v; v.push_back(0); for (int i = 0; i < n; i ++) { int x; cin >> x; v.push_back(x); } vector<ll> pref; pref.push_back(0); for (int i = 1; i <= n; i ++) { pref.push_back(pref.back() + v[i]); } if (pref.back() < mod) { heura(v, pref); } else n2(v, pref); } |
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