백준 1316 - 그룹 단어 체커

#include <iostream>
#include <string>
 
using namespace std;
 
int main(void) {
    int N, answer = 0;
    bool isUsed[26];
    cin >> N;
    string input;
 
    for(int i=0; i<N; i++) {
        cin >> input;
        bool isGroup = true;
 
        for(int j=0; j<26; j++)
            isUsed[j] = false;
 
        for(int j=0; j<input.length(); j++) {
            if(isUsed[input.at(j) - 'a']) {
                isGroup = false;
                break;
            } else {
                isUsed[input.at(j) - 'a'] = true;
                while((j+1 < input.length())) {
                    if(input.at(j) == input.at(j+1))
                        j++;
                    else
                        break;
                }
            }
        }
 
        if(isGroup) {
            answer++; 
        }
    }
 
    cout << answer << endl;
 
    return 0;
}