使用动态规划找出给定字符串中的不同回文子串

String = abcaa

The possible palindromic substrings are : a, b, c, aa, aaa, aba, and aca.

String = “abcd”

a, b, c, and d.

string_name.size();

str.size();

map_name.end();

mp.end();

string_name.substr(pos, len);

str.substr();

#include <iostream>
#include <map>
using namespace std;

//user defined program to find the palindrome substrings
void palindromeSubStrings(string str){
   map<string, int> mp;
   int l = str.size();
   
   //store odd and even length palindrome substrings
   int R[2][l+1];
   
   //Using guards for effortless iteration over the input string and generating all palindrome
   // substrings
   str = "@" + str + "#";
   
   for (int i = 0; i <= 1; i++) {
      int r = 0;  
      R[i][0] = 0;

      int x = 1;
      while (x <= l){
            
         while (str[x - r - 1] == str[x + i + r])
            r++; 
           
         R[i][x] = r;
         int a = 1;
         while ((R[i][x - a] != r - a) && (a < r)){
            R[i][x + a] = min(R[i][x - a],r - a);
            a++;
         }
         r = max(r - a,0);
         x += a;
      }
   }
   //storing the substring without guards
   str = str.substr(1, l);
      
   mp[string(1, str[0])]=1;
   for (int x = 1; x <= l; x++){
      for (int y = 0; y <= 1; y++)
            for (int r = R[y][x]; r > 0; r--)
               mp[str.substr(x - r - 1, 2 * r + y)]=1;
         mp[string(1, str[x])]=1;
   }
      
   //print the palindrome substrings stored in the Hashmap
   cout << "Palindrome substrings are as listed: ";
   map<string, int>::iterator xx;
   for (xx = mp.begin(); xx!=mp.end(); ++xx)
      cout << (*xx).first << endl;
}
   
//Controlling code
int main(){
   //calling the user-defined function and passing a string as argument
   palindromeSubStrings("abcaa");
   return 0;
}

Palindrome substrings are listed as:
a
aa
b
c

#include <iostream>
#include <vector>
using namespace std;
//User defined function to find the palindromic substring 
int find(string str){
   int a = str.size();
   //defined dpg array
      vector<vector<bool> > dpg(a, vector<bool>(a, false));
      for (int x = 0; x < a; x++) {

         dpg[x][x] = 1;
  
         if (x < a && str[x] == str[x + 1]) {
            dpg[x][x + 1] = 1;
         }
      }
   // Finding length of different substrings
   for (int l = 3; l <= a; l++) {
      for (int x = 0; x + l - 1 < a; x++){
         if (str[x] == str[x + (l - 1)]
         && dpg[x + 1][x + (l - 1) - 1]) {
            dpg[x][x + (l - 1)] = true;
         }
      }
   }
 
 
   vector<int> kmp(a, 0);
   for (int x = 0; x < a; x++) {
     
      int y = 0, m = 1;
      while (m + x < a) {
         if (str[y + x] == str[m + x]){
            dpg[m + x - y][m + x] = false;
            kmp[m++] = ++y;
         }
         else if (y > 0) {
            y = kmp[y - 1];
         }
         else {
            kmp[m++] = 0;
         }
      }
   }

   int cnt = 0;
   for (int x = 0; x < a; x++) {
      string str1;
      for (int y = x; y < a; y++) {
         str1 += str[y];
         if (dpg[x][y]) {
            //counting number of palindromic substrings formed using the string
               cnt++;
               cout << str1 << '\n';
         }
      }
   }
   cout << "Total number of palindromes are "
   << cnt << '\n';
   return 0;
}
 
//Controller
int main(){
   string str = "abaa";
   find(str);
   return 0;
}

a
aba
b
aa
Total number of palindromes are 4