#include <iostream>
#include <string>
#include <vector>
 
using namespace std;
 
string solution(string number, int k) {
    string answer = "";
 
    int length = number.size();
 
    int i = 0, j = 0, maxPoint = 0, answerLength = length - k;
    char max;
    for (i = 0; i < answerLength; i++) {
        for (j = maxPoint, max = 0; j <= length - (answerLength - i); j++) {
            if (max < number[j]) {
                max = number[j];
                maxPoint = j + 1;
            }
        }
        answer += max;
    }
    return answer;
}
 
int main() {
    cout << solution("4177252841", 4);
    return 0;
}

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