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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. ll sq(ll x) {
  62. return x * x;
  63. }
  64.  
  65. ll cb(ll x) {
  66. return x * x * x;
  67. }
  68.  
  69. ll n, res;
  70. void solve() {
  71. cin >> n;
  72.  
  73. // Loại 1
  74. res = n * (n + 1) / 2;
  75.  
  76. // Loại 2
  77. for (ll i = 1; sq(i) <= n; ++i) {
  78. res += (sq(i) - sq(i - 1)) * i;
  79. }
  80. ll tmp = sqrt(n);
  81. res += (tmp + 1) * (n - sq(tmp));
  82.  
  83. // Loại 3
  84. for (ll i = 2; cb(i) <= n; ++i) {
  85. res += (cb(i) - cb(i - 1)) * (i - 1);
  86. }
  87. tmp = cbrt(n);
  88. res += tmp * (n - cb(tmp) + 1);
  89.  
  90. cout << res << endl;
  91. }
  92.  
  93. signed main() {
  94. ios::sync_with_stdio(false), cin.tie(nullptr);
  95. srand(time(NULL));
  96. #define name "test"
  97. if (fopen(name".INP", "r")) {
  98. freopen(name".INP", "r", stdin);
  99. freopen(name".OUT", "w", stdout);
  100. }
  101. bool testCase = false;
  102. int numTest = 1;
  103. // cin >> numTest;
  104. forw (i, 1, numTest) {
  105. if (testCase) cout << "Case " << i << ": ";
  106. solve();
  107. }
  108. return 0;
  109. }
  110.  
Success #stdin #stdout 0.01s 5284KB
stdin
1
stdout
3