讲解视频在b站。

试题B：年号字串

#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

int main()
{
    int n;
    cin >> n;
    vector<int> number;
    number.push_back(0);
    for (int i = 0; i < n - 1; i ++ )
    {
        number[0] ++ ;
        for (int j = 0; number[j] == 26; j ++ )
        {
            number[j] = 0;
            if (j + 1 == number.size()) number.push_back(0);
            else number[j + 1] ++ ;
        }
    }

    for (int i = number.size() - 1; i >= 0; i -- ) cout << char('A' + number[i]);
    cout << endl;
}

试题G：完全二叉树的值

#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <limits.h>

using namespace std;

typedef long long LL;

int main()
{
    int n;
    cin >> n;
    LL maxv = INT_MIN, maxv_d = 0;
    for (int i = 0, length = 1, depth = 1; i < n; depth ++, length *= 2)
    {
        LL s = 0;
        for (int j = 0; j < length && i < n; j ++, i ++ )
        {
            int x;
            cin >> x;
            s += x;
        }

        if (s > maxv)
        {
            maxv = s;
            maxv_d = depth;
        }
    }

    cout << maxv_d << endl;

    return 0;
}

试题H：等差数列

#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <limits.h>

using namespace std;

const int N = 100010;

int n;
int a[N];

int gcd(int a, int b)
{
    return b ? gcd(b, a % b) : a;
}

int main()
{
    cin >> n;
    for (int i = 1; i <= n; i ++ ) cin >> a[i];
    sort(a + 1, a + 1 + n);
    for (int i = 2; i <= n; i ++ ) a[i] -= a[1];

    int d = a[2];
    for (int i = 3; i <= n; i ++ ) d = gcd(d, a[i]);

    if (d) cout << a[n] / d + 1 << endl;
    else cout << n << endl;

    return 0;
}