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  1.  
  2. #include <bits/stdc++.h>
  3.  
  4. using namespace std;
  5.  
  6.  
  7. // Warning: Change mod and N according to question
  8. const int mod = (1LL << 31)-1;
  9. const int N = 1e6 + 3;
  10.  
  11. #define int long long
  12. #define MP make_pair
  13. #define F first
  14. #define S second
  15. #define sz(s) ((int)s.size())
  16.  
  17. int rand(int l, int r){
  18.   static std::mt19937 rng(std::chrono::steady_clock::now().time_since_epoch().count());
  19.   std::uniform_int_distribution<int> ludo(l, r); return ludo(rng);
  20. }
  21.  
  22. inline int add(int x, int y, int mod = ::mod) {
  23.   x += y;
  24.   if (x >= mod or x < 0) x %= mod;
  25.   if (x >= 0) return x;
  26.   return x + mod;
  27. } 
  28. inline int mul(int x, int y, int mod = ::mod) {
  29.   if (x >= mod or x + mod < 0) x %= mod;
  30.   if (y >= mod or y + mod < 0) y %= mod;
  31.   x *= y;
  32.   if (x >= mod or x + mod < 0) x %= mod;
  33.   if (x >= 0) return x;
  34.   return x + mod;
  35. }
  36. inline int sub(int x, int y, int mod = ::mod) {
  37.   x -= y;
  38.   if (x + mod < 0 or x >= mod) {
  39.     x %= mod;
  40.   }
  41.   if (x >= 0) return x;
  42.   return x + mod;
  43. }
  44.  
  45. char s[N];
  46.  
  47. struct Hash {
  48.   vector<pair<int,int>> H, pre;
  49.   Hash(const char *s, int N, int b1 = 41, int b2 = 53) :
  50.     H(N + 5), pre(N + 5) {       
  51.     pre[0].F = 1, b1 = rand(37, 1 << 10);
  52.     pre[0].S = 1, b2 = rand(41, 1 << 9);
  53.     int cur1 = 0, cur2 = 0;
  54.     for (int i = 1; i <= N; ++i) {
  55.       pre[i].F = mul(pre[i-1].F, b1);
  56.       pre[i].S = mul(pre[i-1].S, b2);
  57.       cur1 = add(mul(cur1, b1), (s[i] - 'a' + 1));
  58.       cur2 = add(mul(cur2, b2), (s[i] - 'a' + 1));
  59.       H[i].F = cur1, H[i].S = cur2;
  60.     }   
  61.   }
  62.   pair<int,int> get_hash(int l, int r) {
  63.     int rem1 = mul(pre[r-l+1].F, H[l-1].F);
  64.     int rem2 = mul(pre[r-l+1].S, H[l-1].S);
  65.     return MP(sub(H[r].F, rem1), sub(H[r].S, rem2));
  66.   }
  67. };
  68.  
  69.  
  70. signed main() {
  71.   ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  72.   cin >> (s + 1);
  73.   int n = strlen(s + 1);
  74.   Hash ins(s, n);
  75.   vector<int> answer;
  76.   answer.reserve(n);
  77.   for (int len = 1; len <= n; ++len) {
  78.     bool pos = true;
  79.     auto forLen = ins.get_hash(1, len);
  80.     for (int i = len + len; i <= n && pos; i += len) {
  81.       pos &= (forLen == ins.get_hash(i - len + 1, i));      
  82.     }
  83.     int l = n / len * len;
  84.     if (l != n) {
  85.       int rem = n - l;
  86.       pos &= ins.get_hash(1, rem) == ins.get_hash(l + 1, n);
  87.     }
  88.     if (pos) answer.push_back(len);
  89.   }
  90.   for (int x: answer) cout << x << ' ';
  91.   return 0;
  92. }
Success #stdin #stdout 0s 4420KB
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https://ideone.com/9dHdnj
language:
C++14 (gcc 8.3)
created:
4 years ago
visibility:
secret

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