A. 2 * 2 = 5

#include <bits/stdc++.h>

using namespace std;

#define int long long

signed main() {
    int a, b;
    cin >> a >> b;
    cout << a * b + 1;
    return 0;
}

B. Dasturchi Jaloliddin

#include <bits/stdc++.h>

using namespace std;

int main() {
    int n, m, l = 0;
    cin >> n >> m;
    int a[n];
    for (int &i : a) cin >> i;
    for (int i = 0; i < n; ++i) {
        if (a[i] - l > m) return cout << i, 0;
        l = a[i];
    }
    cout << n;
    return 0;
}

C. Humoyun va permutatsiya (EASY)

#include <bits/stdc++.h>

using namespace std;

#define int long long

signed main() {
    int n;
    cin >> n;
    vector<int> a(n);
    for (int &i : a) cin >> i;
    for (int i = 0; i < n; ++i) {
        if (a[i] - i - 1) {
            for (int j = i + 1; j < n; ++j) if (a[j] == i + 1) swap(a[i], a[j]);
            break;
        }
    }
    for (int i : a) cout << i << ' ';
    return 0;
}

D. Humoyun va permutatsiya (HARD)

#include <bits/stdc++.h>

using namespace std;

#define int long long

signed main() {
    int n, m = 1;
    cin >> n;
    vector<int> a(n);
    for (int &i : a) cin >> i;
    for (int i = 0; i < n; ++i) {
        if (a[i] - i - 1) {
            for (int j = i + 1; j < n; ++j) if (a[j] == i + 1) swap(a[i], a[j]);
            m = 0;
            break;
        }
    }
    if (m) swap(a.back(), a[n - 2]);
    for (int i : a) cout << i << ' ';
    return 0;
}

E. Muhammadaziz va XOR

#include <bits/stdc++.h>

using namespace std;

#define int long long

signed main() {
    int n, mx = 0;
    cin >> n;
    vector<int> a(n);
    for (int &i : a) cin >> i;
    for (int i = 1; i < n; ++i) a[i] ^= a[i - 1];
    for (int i = 0; i < n; ++i) for (int j = i; j < n; ++j) mx = max(mx, (i ? a[j] ^ a[i - 1] : a[j]));
    cout << mx;
    return 0;
}