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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. #define faster ios_base::sync_with_stdio(false); cin.tie(NULL)
  4. #define Bit(mask , i) ((mask >> i) & 1)
  5. #define fi first
  6. #define se second
  7. #define _LOG2(nl) 31 - __builtin_clz(nl)
  8. #define c_bit(nl) __builtin_popcount(nl)
  9. #define li pair<long long , int>
  10. #define db double
  11. #define onBit(mask , i) (mask | (1 << i))
  12. #define offBit(mask , i) (mask & (~(1 << i)))
  13.  
  14. const long long MOD = 1e9 + 7;
  15. const long long INF = 1e14;
  16. const int N = 1e6 + 7;
  17. int pre[N] , z[N] , kmp[N];
  18. string s;
  19. int n;
  20.  
  21. void inp(){
  22.     cin >> s;
  23.     n = s.size();
  24.     s = "L" + s;
  25. }
  26.  
  27. void solve(){
  28.     int k = kmp[1] = 0;
  29.     for (int i = 2 ; i <= n ; ++i){
  30.         while (k > 0 && s[i] != s[k + 1]) k = kmp[k];
  31.         kmp[i] = s[i] == s[k + 1] ? ++k : 0;
  32.     }
  33.     for (int i = 2 , l = 2 , r = 1 ; i <= n ; ++i){
  34.         if (i <= r)
  35.             z[i] = min(r - i + 1 , z[i - l + 1]);
  36.         while (i + z[i] <= n && s[1 + z[i]] == s[i + z[i]])
  37.             ++z[i];
  38.         if (i + z[i] - 1 > r){
  39.             l = i;
  40.             r = i + z[i] - 1;
  41.         }
  42.     }
  43.     for (int i = 1 ; i <= n ; ++i) if (z[i] != 0){
  44.         ++pre[1];
  45.         --pre[z[i] + 1];
  46.     }
  47.     for (int i = 1 ; i <= n ; ++i){
  48.         pre[i] += pre[i - 1];
  49.     }
  50.     k = kmp[n];
  51.     while (k > 0){
  52.         if (pre[k] < 2){
  53.             k = kmp[k];
  54.             continue;
  55.         }
  56.         for (int i = 1 ; i <= k ; ++i) cout << s[i];
  57.         return;
  58.     }
  59.     cout << "No solution!";
  60. }
  61.  
  62. int main(){
  63. //	freopen("xhmax.inp" , "r" , stdin);
  64. //	freopen("xhmax.out" , "w" , stdout);
  65.     faster;
  66.     inp();
  67.     solve();
  68.     return 0;
  69. }
  70.  
Success #stdin #stdout 0s 5320KB
comments (?)
stdin 
Standard input is empty
stdout 
No solution!
https://ideone.com/D8tuVt
language:
C++14 (gcc 8.3)
created:
1 day ago
visibility:
public

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