347E - Number Transformation II - CodeForces Solution

#include<iostream>
#include <unordered_set>
#include <vector>
 int main()
 {
    std::unordered_set<int> x_set;
std::vector<int> x;
int n=0;
std::cin >> n;
int temp=0;
for (int i = 0; i < n; i++)
{
    std::cin >> temp;
    if (x_set.count(temp) == 0) 
    {
        x_set.insert(temp);
        x.push_back(temp);
    }
}
 int result = 0;
 int a=0;
 int b=0;
 std::cin >> a >> b;
 while (a != b) 
 {
    std::vector<int> xs;
int bestA = a - 1;
for (int i = 0; i < x.size(); i++) {
    int temp = x[i];
    int p = a / temp * temp;

    if (p >= b) {
        xs.push_back(temp);
        bestA = std::min(bestA, p);
    }
}
x = xs;
a = bestA;
result++;
 }
   std::cout << result << '\n';
    return 0;
 }/*1698400788.3892748*/