fork(1) download
copy 
  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. #define int              long long int
  4. #define double           long double
  5. #define print(a)         for(auto x : a) cout << x << " "; cout << endl
  6.  
  7.  
  8. const int M = 1000000007;
  9. const int N = 3e5+9;
  10. const int INF = 2e9+1;
  11. const int LINF = 2000000000000000001;
  12.  
  13. inline int power(int a, int b, int mod=M) {
  14.     int x = 1;
  15.     a %= mod;
  16.     while (b) {
  17.         if (b & 1) x = (x * a) % mod; 
  18.         a = (a * a) % mod;
  19.         b >>= 1;
  20.     }
  21.     return x;
  22. }
  23.  
  24.  
  25. //_ ***************************** START Below *******************************
  26.  
  27.  
  28.  
  29.  
  30. string a;
  31.  
  32. bool isPossible(int n, int mid){
  33.  
  34. 	if (mid == 0) return true;
  35.  
  36. 	int P = 31;
  37. 	int MOD = 1e9 + 7;
  38. 	int p_pow = 1;
  39.  
  40. 	for (int i = 0; i < mid - 1; i++) {
  41. 		p_pow = (p_pow * P) % MOD;
  42. 	}
  43.  
  44. 	int s = 0;
  45. 	int e = 0;
  46. 	int hash = 0;
  47.  
  48. 	//* substring -> index
  49. 	unordered_map<int,int> mp;
  50.  
  51. 	while(e < n){
  52. 		hash = (hash * P + (a[e] - 'a' + 1)) % MOD;
  53.  
  54. 		if(e - s + 1 < mid){
  55. 			e++;
  56. 		}
  57. 		else{
  58. 			if(mp.count(hash)){
  59. 				if(s >= mp[hash] + mid) return true;	
  60. 			}
  61. 			else{
  62. 				mp[hash] = s;
  63. 			}
  64.  
  65.  
  66. 			hash = (hash - (a[s] - 'a' + 1) * p_pow) % MOD;
  67. 			if (hash < 0) hash += MOD;
  68.  
  69. 			e++;
  70. 			s++;
  71. 		}
  72. 	}
  73. 	return false;
  74. }
  75.  
  76.  
  77. int consistency(int n){
  78.  
  79. 	int s = 0;
  80. 	int e = n/2+1;
  81.  
  82.  
  83. 	while(s<e){
  84. 		int mid = s + (e-s+1)/2;
  85.  
  86. 		if(isPossible(n, mid)){
  87. 			s = mid;
  88. 		}
  89. 		else{
  90. 			e = mid-1;
  91. 		}
  92.  
  93. 	}
  94.  
  95.  
  96.  
  97. 	return e;
  98. }
  99.  
  100.  
  101.  
  102.  
  103.  
  104.  
  105.  
  106.  
  107.  
  108.  
  109.  
  110.  
  111.  
  112.  
  113.  
  114.  
  115.  
  116.  
  117.  
  118. void solve() {
  119.  
  120.     cin >> a;
  121.     int n = a.size();
  122.  
  123.     cout << consistency(n) << endl;
  124.  
  125.  
  126. }
  127.  
  128.  
  129.  
  130.  
  131.  
  132. int32_t main() {
  133.     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  134.  
  135.     int t = 1;
  136.     // cin >> t;
  137.     while (t--) {
  138.         solve();
  139.     }
  140.  
  141.     return 0;
  142. }
Success #stdin #stdout 0s 5316KB
comments (?)
stdin
copy 
abacdabaweacda
stdout
copy 
4
https://ideone.com/Su4SU9
language:
C++14 (gcc 8.3)
created:
1 day ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!