Sanalista

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

using namespace std;

struct letter {
		char c;
		int num;
};

bool is_even(int num) {
    return !(num & 1);
}

bool has_even_letters(string str) {
	vector<letter> letters;
	letters.push_back(letter());
	
	// get number of characers in the word
	for (uint i = 0; i < str.length(); i++) {
	    bool applied = false;
		for (uint x = 1; x < letters.size(); x++) {
		    // add to current counter, if found
			if (str.at(i) == letters[x].c) {
				letters[x].num++;
				applied = true;
				break;
			}
		}
		// create new counter, if not already existing
		if (!applied) { 
		    letter l;
		    l.c = str.at(i);
		    l.num = 1;
		    letters.push_back(l);
		}

	}
	
	// check if there is even number of each letter
	for (uint i = 1; i < letters.size(); i++) { // starts from 1, because of the empty struct at 0
	    if (!is_even(letters[i].num)) return false;
	}
	return true;
}

int main() {    
	int num;
	vector<string> str;

	cin >> num;
	for (int i = 0; i < num; i++) {
	    string s;
		cin >> s;
		str.push_back(s);
	}

    int counter = 0; 
    
    // get number of the words
    for (uint i = 0; i < str.size(); i++) {
        if (has_even_letters(str[i])) counter++;
    }
	cout << counter;
	
	return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED