[골3] 2812 - 크게 만들기

#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <stack>
#include <queue>

using namespace std;

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);
    int n, k;
    string str;
    vector<char> v;
    cin >> n >> k >> str;
    for (int i = 0; i < str.size(); i++)
    {
        while (k > 0 && 
               !v.empty() &&
               v.back() < str[i])
        {
            v.pop_back();
            k--;
        }
        v.push_back(str[i]);
    }
    while (k--) 
        v.pop_back();

    for (int i = 0; i < v.size(); i++) 
        cout << v[i];

    return 0;
}