C++入门同步记录#9_using namespace std; int mian(){ long long n; cin>-优快云博客

本文链接：https://blog.youkuaiyun.com/Norikage/article/details/115100756

本文探讨了四个不同编程挑战，涉及计数因子的计算、数字序列求和、特定数字出现频率统计、以及自动推理算法。还涵盖了自动驾驶中的感知系统和数据分析技术。这些内容展示了信息技术在算法优化、数据处理和现代应用中的实践应用。

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/* #include<iostream>
using namespace std;
int main() {
    long long n, ans = 0;
    cin >> n;
    for (int i = 1; i <= n; i++) {
        long long factor = 1;
        for (int j = 1; j <= i; j++)
            factor *= j;
        ans += factor;
    }
    cout << ans << endl;
    return 0;
} */

#include<iostream>
using namespace std;
int main() {
    long long n, ans = 0;
    long long factor = 1;
    cin >> n;
    for (int i = 1; i <= n; i++) {
        factor *= i;
        ans += factor;
    }
    cout << ans << endl;
    return 0;
}


#include<iostream>
using namespace std;
int main() {
    int n, x, ans;
    cin >> n >> x;
    for (int i = 1; i <= n; i++){
        int tmp = i, num;
        while (tmp != 0) {
            num = tmp % 10;
            if (num == x)
                ans++;
            tmp /= 10;
        }
    }
    cout << ans << endl;
    return 0;
}


#include<iostream>
using namespace std;
int main() {
    int k, ans = 0;
    cin >> k;
    for (double Sn = 0; Sn <= k; ans++, Sn += 1.0 / ans)
    cout << ans;
    return 0;
}


#include<iostream>
using namespace std;
int main() {
    int k, coin = 0, day = 0;
    cin >> k;
    for (int i = 1;; i++)
        for (int j = 1; j <= i; j++) {
            coin += i; day++;
            if (day == k) {
                cout << coin << endl;
                return 0;
            }
        }
    return 0;
}


#include<iostream>
using namespace std;
int main() {
    int s = 0, n;
    cin >> n;
    for (int i = 0; i <= n; i++)
        s += i;
    cout << s;
    return 0;
}



#include<iostream>
using namespace std;
int main() {
    int s = 0, i = 0, n;
    cin >> n;
    while (n--) s += ++i;
    cout << s;
    return 0;
}