Factory_Machines.cpp

#include<bits/stdc++.h>
using namespace std;

#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define nline "\n" 
#define int long long
#define fo(i,n) for(int i = 0;i<n;i++)
#define pb push_back
#define F first
#define S second
typedef long double ld;
typedef vector<signed> vi;
typedef vector<vector<signed>> vvi;
typedef vector<int> vll;
typedef vector<vector<int>> vvll;
const int mod = 1e9+7;
long double pi = acos(-1.0); const double EPS = 1e-9;

int myceil(int a , int b){return (a+b-1)/b;}
int myround(int a , int b){return (2*a+b)/(2*b);}

int n, t;
vector<int> arr;
int check(int mid){
    // can we produce t prod in mid sec
    int total_prod = 0;
    fo(i,n){
        total_prod += mid/arr[i];
    }
    if(total_prod >= t) return 1;
    return 0;
}

signed main(){
    IOS;

    #ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout); 
    #endif

    cin >> n >> t;
    arr.resize(n);
    fo(i,n){
        cin >> arr[i];
    }

    int low = 0, high = t*arr[0], ans = -1;
    while(low <= high){
        int mid = low + (high-low)/2;
        if(check(mid)==1){
            ans = mid;
            high = mid - 1;
        }else{
            low = mid + 1;
        }
    }
    cout << ans;
    
    
    
    

}