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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<vector<int>> dp(n, vector<int>(n, 0));
  35.  
  36.  
  37.     for(int gap=0; gap<n; gap++){
  38.         for(int i=0, j=gap; j<n; i++, j++){
  39.             if(gap == 0){
  40.                 dp[i][j] = 1;
  41.             }
  42.             else if(gap == 1){
  43.                 if(a[i] == a[j]) dp[i][j] = 3;
  44.                 else dp[i][j] = 2;
  45.             }
  46.             else{
  47.                 if(a[i] == a[j]){
  48.                     dp[i][j] = dp[i][j-1] + dp[i+1][j] + 1;
  49.                 }
  50.                 else{
  51.                     dp[i][j] = dp[i][j-1] + dp[i+1][j] - dp[i+1][j-1];
  52.                 }
  53.             }
  54.         }
  55.     }
  56.  
  57.     return dp[0][n-1];
  58.  
  59. }
  60.  
  61.  
  62.  
  63.  
  64.  
  65.  
  66.  
  67.  
  68.  
  69.  
  70.  
  71.  
  72.  
  73.  
  74.  
  75. int practice(int n){
  76.  
  77.  
  78.     return 0;
  79. }
  80.  
  81.  
  82.  
  83.  
  84.  
  85. void solve() {
  86.  
  87.  
  88.     cin >> a;;
  89.  
  90.     int n = a.size();
  91.  
  92.     cout << consistency(n) << endl;
  93.  
  94.  
  95. }
  96.  
  97.  
  98.  
  99.  
  100.  
  101. int32_t main() {
  102.     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  103.  
  104.     int t = 1;
  105.     // cin >> t;
  106.     while (t--) {
  107.         solve();
  108.     }
  109.  
  110.     return 0;
  111. }
Success #stdin #stdout 0s 5320KB
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https://ideone.com/sOtc4M
language:
C++14 (gcc 8.3)
created:
10 hours ago
visibility:
public

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