Question

How to print the number of substrings with exactly k distinct characters in C++

Answer 1

#include <string>
#include <vector>
#include <set>
#include <iostream>

void PrintSubstringWithKDistinctChars(const std::string &s, int k) {
	std::vector<std::string> substring;
	int size = s.length();

	for (int i = 0; i < size; i++) {
		char ch = s[i];
		std::string tmp = "";
		tmp += ch;
		std::set<char> st;
		st.insert(ch);

		for (int j = i + 1; j < size; j++) {
			char next_ch = s[j];
			st.insert(next_ch);
			tmp += next_ch;
			
			if (tmp.length() >= k && st.size() == k) {
				substring.push_back(tmp);
			}
		}
	}

	for (auto const &sub: substring) {
        std::cout << sub << " ";
    }
}

int main()
{
	std::string str = "characters";
	int k = 4;

	PrintSubstringWithKDistinctChars(str, k);
}




/*
run:

char chara charac harac aract ract acte cter ters 

*/

 

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