构成给定字符串所需的字符串前缀和后缀的最小数量

#include <bits/stdc++.h>
using namespace std;
// function to find the required number of substrings
int count(string str1, string str2){
   unordered_set<string> st; // set to store the strings from the prefix and suffix 
   string temp = "";// string to store the prefixes and suffixes 
   int len1 = str1.size(); // size of the first string 
   int len2 = str2.size(); // getting size of the second 
   
   // getting prefixes of string second 
   for (int i = 0; i < len2; i++){
      temp += str2[i]; // adding the characters to temporary string
      st.insert(temp); // insert current string to set 
   }
   
   // getting all the sufixes 
   for (int i = len2-1; i >= 0; i--){
      temp = str2.substr(i); // getting suffixes		
      st.insert(temp); // adding suffixes to the set 
   }
   // Initialize memo array to store the answer
   int memo[len1+1];
   memset(memo, -1, sizeof(memo)); // initializing array 
   memo[0] = 0; 
   
   // applying the concepts of dp 
   // traversing over the main string and will try to 
   // partition string into chunks 
	for (int i = 0; i < len1; i++){
      for (int j = 1; j <= len1 - i; j++){
		   // check if the set contain current substring 
         if (st.find(str1.substr(i, j)) != st.end()){
            if (memo[i] == -1){
               continue;
            }
            if (memo[i + j] == -1){
               memo[i + j] = memo[i] + 1;
            }
            else {
               memo[i + j] = min(memo[i + j], memo[i] + 1);
            }
         }
      }
   }
   // Return the answer
   return memo[len1];
}
int main(){
   string str1 = "tutorialpoints";
   string str2 = "pointstutorial";
   // calling function to find the minimum number of substrings required
   cout <<"The minimum count of prefixes and suffixes of a string required to form given string is "<<count(str1, str2)<<endl;
   return 0;
}