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  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. int consistency(int n){
  33.  
  34. 	vector<int> dpA1(n+1, 0);
  35. 	vector<int> dpA2(n+1, 0);
  36. 	vector<int> dpB1(n+1, 0);
  37. 	vector<int> dpB2(n+1, 0);
  38.  
  39. 	dpA1[0] = dpA2[0] = dpB1[0] = dpB2[0] = 0;
  40.  
  41. 	if(a[0] == 'a') dpA1[1] = 1;
  42. 	else dpB1[1] = 1;
  43.  
  44. 	for(int i=2; i<=n; i++){
  45.  
  46. 		if(a[i-1] == 'a'){
  47. 			dpA1[i] = max(dpB1[i-1] , dpB2[i-1]) + 1;
  48. 		}
  49. 		if(a[i-1] == 'a' && a[i-2] == 'a'){
  50. 			dpA2[i] = max( dpB1[i-2] , dpB2[i-2] ) + 2;
  51. 		}
  52.  
  53. 		if(a[i-1] == 'b'){
  54. 			dpB1[i] = max(dpA1[i-1] , dpA2[i-1] ) + 1;
  55. 		}
  56. 		if(a[i-1] == 'b' && a[i-2] == 'b'){
  57. 			dpB2[i] = max( dpA1[i-2] , dpA2[i-2] ) + 2;
  58. 		}
  59.  
  60. 	}
  61.  
  62.  
  63. 	int ans = 0;
  64. 	for(int i=0; i<=n; i++){
  65. 		ans = max({ans, dpA1[i], dpA2[i] , dpB1[i] , dpB2[i] });
  66. 	}
  67.  
  68. 	return ans;
  69. }
  70.  
  71.  
  72.  
  73.  
  74.  
  75.  
  76.  
  77.  
  78.  
  79.  
  80.  
  81.  
  82.  
  83.  
  84.  
  85. int practice(int n){
  86.  
  87.  
  88.     return 0;
  89. }
  90.  
  91.  
  92.  
  93.  
  94.  
  95. void solve() {
  96.  
  97.     int n;
  98.  
  99.     cin >> a;
  100.     n = a.size();
  101.  
  102.     cout << consistency(n) << endl;
  103.  
  104.  
  105. }
  106.  
  107.  
  108.  
  109.  
  110.  
  111. int32_t main() {
  112.     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  113.  
  114.     int t = 1;
  115.     // cin >> t;
  116.     while (t--) {
  117.         solve();
  118.     }
  119.  
  120.     return 0;
  121. }
Success #stdin #stdout 0s 5320KB
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https://ideone.com/cYZQwF
language:
C++14 (gcc 8.3)
created:
4 hours ago
visibility:
public

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