partition epta

#include <iostream>
#include <vector>
#include <cstdlib>

using namespace std;

int Partition(vector<int> &vec, int N, int k_static){
    int first_elem = 0;
    int last_elem = N - 1;
    int i = 0, j = 0;
    while (1){
        int pivot_pos = rand() % (last_elem - first_elem + 1  ) + (first_elem);
        i = first_elem, j = first_elem;
        swap(vec[last_elem], vec[pivot_pos]);
        for (; j != last_elem;){
            if (vec[j] < vec[last_elem]){
                swap(vec[j], vec[i]);
                i++;
            }
            j++;
        }
        swap(vec[last_elem], vec[i]);
        if (i < k_static){
            first_elem = i + 1;
            last_elem;
        }
        else if (i == k_static){
            return vec[i];
        }
        else{
            first_elem = 0;
            last_elem = i - 1;
        }
    }
}

int main(){
    int N = 0;
    cin >> N;
    int k_static = 0;
    cin >> k_static;
    vector<int> vect(N);
    for (int i = 0; i < N; i++){
        cin >> vect[i];
    }
    int answer = Partition(vect, N, k_static);
    cout << answer;
    return 0;
}