C++:

#include <bits/stdc++.h>
#define int long long
using namespace std;
signed main()
{
    int n, k; cin >> n;
    int a[n];
    for (int i = 0; i < n; i ++) cin >> a[i];
    cin >> k;
    bool Check= false;
    for (int i = 0; i < n; i++)
    {
        if (a[i] == k)
        {
            cout << i + 1 << " ";
            Check = true;
        }
    }
    if (!Check) cout << -1;
}

Python:

n = int(input())
a = list(map(int, input().split()))
k = int(input())
check = False
for i in range(n):
    if a[i] == k:
        print(i + 1, end=" ")
        check = True
if not check:
    print(-1)

Chúc bn học tốt!

$\color{Red}{\triangleright \triangleright\ \color{ Red}{\text{ThienPhuc123} \triangleleft \triangleleft}}$

$#doanthevu$

Code C++ :

#include <bits/stdc++.h>
#define ll long long
using namespace std;
int main() {
    ll n, k;
    cin >> n;
    ll arr[n];
    for (ll i = 0; i < n; i++) {
        cin >> arr[i];
    }
    cin >> k;
    bool tk= false;
    for (ll i = 0; i < n; i++) {
        if (arr[i] == k) {
            cout << i + 1 << " "; 
            tk= true;
        }
    }
    if (!tk) {
        cout << -1;
    }
    return 0;
}