#include <bits/stdc++.h> #ifndef ONLINE_JUDGE # pragma GCC diagnostic warning "-Wall" # pragma GCC diagnostic warning "-Wextra" # pragma GCC diagnostic warning "-Wformat=2" # pragma GCC diagnostic warning "-Wnull-dereference" # pragma GCC diagnostic warning "-Wduplicated-branches" # pragma GCC diagnostic warning "-Wduplicated-cond" # pragma GCC diagnostic warning "-Wfloat-equal" # pragma GCC diagnostic warning "-Wshadow" # pragma GCC diagnostic warning "-Wconversion" # pragma GCC diagnostic warning "-Wlogical-op" # pragma GCC diagnostic warning "-Wvector-operation-performance" # pragma GCC diagnostic warning "-Wdisabled-optimization" # pragma GCC diagnostic warning "-Wunsafe-loop-optimizations" # pragma GCC diagnostic warning "-Wdouble-promotion" #endif #pragma GCC target "arch=ivybridge", "tune=ivybridge" #if defined(ONLINE_JUDGE) || !defined(__OPTIMIZE__) # pragma GCC optimize "Ofast", "inline", "unroll-loops", "ipa-pta", "no-rtti", \ "no-exceptions", "nothrow-opt", "strict-enums", "stdarg-opt", "tracer" # pragma GCC target "inline-all-stringops" #endif #define rangeof(c) (c).begin(), (c).end() using namespace std; using uint = unsigned int; using ll = long long; using ull = unsigned long long; using ld = long double; int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); int const mod = 1000000007; int n; cin >> n; vector<ll> nums(n); vector<ll> pref_sum(n + 1, 0); bool is_sum_over_mod = false; for(int i = 0; i < n; i++) { cin >> nums[i]; pref_sum[i + 1] = (pref_sum[i] + nums[i]) % mod; is_sum_over_mod |= pref_sum[i] + nums[i] >= mod; } auto num_sum = [&](int a, int b) -> ll { return (pref_sum[b + 1] - pref_sum[a] + mod) % mod; }; if(n <= 3000 || is_sum_over_mod) { vector<vector<ll>> dp(n, vector<ll>(n, 0)); dp[0][0] = 1; for(int i = 1; i < n; i++) { // dodajemy do istniejacego albo robimy nowy for(int j = 0; j < i; j++) { dp[i][j] = dp[i - 1][j]; if(j <= i - 1 && num_sum(j, i - 1) % 2 == 0) { dp[i][i] += dp[i - 1][j]; dp[i][i] %= mod; } } } ll result = 0; for(int i = 0; i < n; i++) { if(num_sum(i, n - 1) % 2 != 0) continue; result = (result + dp[n - 1][i]) % mod; } cout << result << "\n"; } else { // assuming the sum of all numbers doesn't ever exceed 10^9+7 if(is_sum_over_mod) { cout << "NIE\n"; return 0; } int const m = 2; vector<array<array<ll, 2>, 2>> dp(n + 1); dp[0][0][0] = 1; for(int i = 1; i <= n; i++) { for(int prev = 0; prev < m; prev++) { // dodajemy do istniejacego albo robimy nowy dla nums[i - 1] for(int curr = 0; curr < m; curr++) { dp[n][prev][curr] = dp[n][prev][(curr - nums[i - 1] % m + m) % m]; } dp[n][prev][nums[i - 1] % m] += dp[n][prev][prev]; dp[n][prev][nums[i - 1] % m] %= mod; } } cout << dp[n][0][0] << "\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 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 | #include <bits/stdc++.h> #ifndef ONLINE_JUDGE # pragma GCC diagnostic warning "-Wall" # pragma GCC diagnostic warning "-Wextra" # pragma GCC diagnostic warning "-Wformat=2" # pragma GCC diagnostic warning "-Wnull-dereference" # pragma GCC diagnostic warning "-Wduplicated-branches" # pragma GCC diagnostic warning "-Wduplicated-cond" # pragma GCC diagnostic warning "-Wfloat-equal" # pragma GCC diagnostic warning "-Wshadow" # pragma GCC diagnostic warning "-Wconversion" # pragma GCC diagnostic warning "-Wlogical-op" # pragma GCC diagnostic warning "-Wvector-operation-performance" # pragma GCC diagnostic warning "-Wdisabled-optimization" # pragma GCC diagnostic warning "-Wunsafe-loop-optimizations" # pragma GCC diagnostic warning "-Wdouble-promotion" #endif #pragma GCC target "arch=ivybridge", "tune=ivybridge" #if defined(ONLINE_JUDGE) || !defined(__OPTIMIZE__) # pragma GCC optimize "Ofast", "inline", "unroll-loops", "ipa-pta", "no-rtti", \ "no-exceptions", "nothrow-opt", "strict-enums", "stdarg-opt", "tracer" # pragma GCC target "inline-all-stringops" #endif #define rangeof(c) (c).begin(), (c).end() using namespace std; using uint = unsigned int; using ll = long long; using ull = unsigned long long; using ld = long double; int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); int const mod = 1000000007; int n; cin >> n; vector<ll> nums(n); vector<ll> pref_sum(n + 1, 0); bool is_sum_over_mod = false; for(int i = 0; i < n; i++) { cin >> nums[i]; pref_sum[i + 1] = (pref_sum[i] + nums[i]) % mod; is_sum_over_mod |= pref_sum[i] + nums[i] >= mod; } auto num_sum = [&](int a, int b) -> ll { return (pref_sum[b + 1] - pref_sum[a] + mod) % mod; }; if(n <= 3000 || is_sum_over_mod) { vector<vector<ll>> dp(n, vector<ll>(n, 0)); dp[0][0] = 1; for(int i = 1; i < n; i++) { // dodajemy do istniejacego albo robimy nowy for(int j = 0; j < i; j++) { dp[i][j] = dp[i - 1][j]; if(j <= i - 1 && num_sum(j, i - 1) % 2 == 0) { dp[i][i] += dp[i - 1][j]; dp[i][i] %= mod; } } } ll result = 0; for(int i = 0; i < n; i++) { if(num_sum(i, n - 1) % 2 != 0) continue; result = (result + dp[n - 1][i]) % mod; } cout << result << "\n"; } else { // assuming the sum of all numbers doesn't ever exceed 10^9+7 if(is_sum_over_mod) { cout << "NIE\n"; return 0; } int const m = 2; vector<array<array<ll, 2>, 2>> dp(n + 1); dp[0][0][0] = 1; for(int i = 1; i <= n; i++) { for(int prev = 0; prev < m; prev++) { // dodajemy do istniejacego albo robimy nowy dla nums[i - 1] for(int curr = 0; curr < m; curr++) { dp[n][prev][curr] = dp[n][prev][(curr - nums[i - 1] % m + m) % m]; } dp[n][prev][nums[i - 1] % m] += dp[n][prev][prev]; dp[n][prev][nums[i - 1] % m] %= mod; } } cout << dp[n][0][0] << "\n"; } } |