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  1. //#pragma GCC optimize("O3", "unroll-loops")
  2. //#pragma GCC target("avx2", "bmi", "bmi2", "lzcnt", "popcnt")
  3.  
  4. #include <bits/stdc++.h>
  5. #define ldb long double
  6. //#define double ldb
  7. #define db double
  8. #define unomap unordered_map
  9. #define unoset unordered_set
  10. #define endl '\n'
  11. #define str string
  12. #define strstr stringstream
  13. #define sz(a) (int)a.size()
  14. #define ll long long
  15. //#define int ll
  16. #define pii pair <int, int>
  17. #define pll pair <ll, ll>
  18. #define Unique(a) a.resize(unique(all(a)) - a.begin())
  19. #define ull unsigned ll
  20. #define fir first
  21. #define sec second
  22. #define idc cin.ignore()
  23. #define lb lower_bound
  24. #define ub upper_bound
  25. #define all(s) s.begin(), s.end()
  26. #define rev reverse
  27. #define gcd __gcd
  28. #define pushb push_back
  29. #define popb pop_back
  30. #define pushf push_front
  31. #define popf pop_front
  32. #define mul2x(a, x) a << x
  33. #define div2x(a, x) a >> x
  34. #define lcm(a, b) (a / __gcd(a, b) * b)
  35. #define log_base(x, base) log(x) / log(base)
  36. #define debug cerr << "No errors!"; exit(0);
  37. #define forw(i, a, b) for (int i = a; i <= b; ++i)
  38. #define forw2(i, a, b) for (ll i = a; i <= b; ++i)
  39. #define fors(i, a, b) for (int i = a; i >= b; --i)
  40. #define fors2(i, a, b) for (ll i = a; i >= b; --i)
  41. #define pqueue priority_queue
  42. #define sqrt sqrtl
  43. #define i128 __int128
  44. #define popcount __builtin_popcountll
  45. #define BIT(x, i) (((x) >> (i)) & 1)
  46. #define MASK(x) ((1LL) << (x))
  47. #define want_digit(x) cout << fixed << setprecision(x);
  48. #define excuting_time 1000.0 * clock() / CLOCKS_PER_SEC
  49. #define mapa make_pair
  50. using namespace std;
  51. const int MOD = 1e9 + 7; // 998244353
  52. const int inf = 1e9;
  53. const ll INF = 1e18;
  54. const int N = 2e5;
  55.  
  56. mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
  57. ll random(const ll &L, const ll &R) {
  58. return uniform_int_distribution<ll> (L, R) (rng);
  59. }
  60.  
  61. int n, a[N + 5];
  62. void solve() {
  63. cin >> n;
  64. forw (i, 1, n) cin >> a[i];
  65. ll ans = 0;
  66. forw (i, 1, n) forw (j, i + 1, n) forw (k, j + 1, n) {
  67. if ((((a[i] * a[j]) % 2) * a[j]) % 2 == 0) ++ans;
  68. }
  69. cout << ans << endl;
  70. }
  71.  
  72. signed main() {
  73. ios::sync_with_stdio(false), cin.tie(nullptr);
  74. srand(time(NULL));
  75. #define name "test"
  76. /*
  77.   if (fopen(name".INP", "r")) {
  78.   freopen(name".INP", "r", stdin);
  79.   freopen(name".OUT", "w", stdout);
  80.   }
  81.   */
  82. bool testCase = false;
  83. int numTest = 1;
  84. // cin >> numTest;
  85. forw (i, 1, numTest) {
  86. if (testCase) cout << "Case " << i << ": ";
  87. solve();
  88. }
  89. return 0;
  90. }
  91.  
  92. /*
  93.   /\__/\
  94.  (=^.^= )
  95.  (") (")_/
  96. */
  97.  
Success #stdin #stdout 0.01s 5284KB
stdin
4
8 3 6 4
stdout
4