#include <bits/stdc++.h> using namespace std; typedef long long LL; typedef pair<int, int> PII; typedef pair<LL, LL> PLL; typedef vector<int> VI; const int INF = 1000000009; const LL LINF = 1000000000000000009LL; #define FOR(i, b, e) for (int i = b; i <= e; ++i) #define FORD(i, b, e) for (int i = b; i >= e; --i) #define REP(i, n) FOR (i, 0, n - 1) #define REV(i, n) FORD (i, n - 1, 0) #define PB push_back #define PP pop_back #define MP make_pair #define MT make_tuple #define ST first #define ND second #define SZ(c) (int)(c).size() #define ALL(c) (c).begin(), (c).end() #define UNIQ(c) (c).erase(unique(ALL(c)), (c).end()); // #include <ext/pb_ds/assoc_container.hpp> // #include <ext/pb_ds/hash_policy.hpp> // using namespace __gnu_pbds; // typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set; /*find_by_order() order_of_key()*/ template <typename T, typename S> ostream &operator<<(ostream &out, const pair<T, S> &v) { return (out << "(" << v.ST << ", " << v.ND << ")"); } #define DEBUG(s) s #ifdef local_comp #define PRINT(V) cout << "#" << #V << ": " << V << endl; #else #define PRINT(v) #endif const int N = 300005; const LL MD2 = 2000000014; const LL MD = 1000000007; int n; int tab[N]; LL pref[N]; LL dp[N]; int main() { #ifndef local_comp ios::sync_with_stdio(0); cin.tie(0); #endif cin >> n; FOR (i, 1, n) cin >> tab[i]; FOR (i, 1, n) { pref[i] = pref[i - 1] + tab[i]; } FOR (i, 1, n) { if (((pref[i] % MD) & 1) == 0) { dp[i]++; dp[i] %= MD; // cout << "[1.." << i << "] "; } FOR (j, 2, i) { if ((((pref[i] - pref[j - 1]) % MD) & 1) == 0) { dp[i] += dp[j - 1]; dp[i] %= MD; // cout << "[" << j << ".." << i << "] "; } } } // cout << "res: "; cout << dp[n] << "\n"; // if (mop[n]) // { // cout << "0"; // return 0; // } // FOR (i, 1, n) // cout << pref[i] << " "; // cout << 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 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 | #include <bits/stdc++.h> using namespace std; typedef long long LL; typedef pair<int, int> PII; typedef pair<LL, LL> PLL; typedef vector<int> VI; const int INF = 1000000009; const LL LINF = 1000000000000000009LL; #define FOR(i, b, e) for (int i = b; i <= e; ++i) #define FORD(i, b, e) for (int i = b; i >= e; --i) #define REP(i, n) FOR (i, 0, n - 1) #define REV(i, n) FORD (i, n - 1, 0) #define PB push_back #define PP pop_back #define MP make_pair #define MT make_tuple #define ST first #define ND second #define SZ(c) (int)(c).size() #define ALL(c) (c).begin(), (c).end() #define UNIQ(c) (c).erase(unique(ALL(c)), (c).end()); // #include <ext/pb_ds/assoc_container.hpp> // #include <ext/pb_ds/hash_policy.hpp> // using namespace __gnu_pbds; // typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set; /*find_by_order() order_of_key()*/ template <typename T, typename S> ostream &operator<<(ostream &out, const pair<T, S> &v) { return (out << "(" << v.ST << ", " << v.ND << ")"); } #define DEBUG(s) s #ifdef local_comp #define PRINT(V) cout << "#" << #V << ": " << V << endl; #else #define PRINT(v) #endif const int N = 300005; const LL MD2 = 2000000014; const LL MD = 1000000007; int n; int tab[N]; LL pref[N]; LL dp[N]; int main() { #ifndef local_comp ios::sync_with_stdio(0); cin.tie(0); #endif cin >> n; FOR (i, 1, n) cin >> tab[i]; FOR (i, 1, n) { pref[i] = pref[i - 1] + tab[i]; } FOR (i, 1, n) { if (((pref[i] % MD) & 1) == 0) { dp[i]++; dp[i] %= MD; // cout << "[1.." << i << "] "; } FOR (j, 2, i) { if ((((pref[i] - pref[j - 1]) % MD) & 1) == 0) { dp[i] += dp[j - 1]; dp[i] %= MD; // cout << "[" << j << ".." << i << "] "; } } } // cout << "res: "; cout << dp[n] << "\n"; // if (mop[n]) // { // cout << "0"; // return 0; // } // FOR (i, 1, n) // cout << pref[i] << " "; // cout << endl; return 0; } |