第三届越秀区中小学生智能编程线上比赛--C++入门组题解报告

T1 时间转换

#include <iostream>
using namespace std;

int main()
{
    int s;
    cin >> s;
    int hh = s / 3600 % 24;
    if(hh < 12)
    {
        cout << "AM ";
    }
    else
    {
        cout << "PM ";
        hh %= 12;
    }
    if(hh < 10)
    {
        cout << '0';
    }
    cout << hh << ':';

    int mm = s % 3600 / 60;
    if(mm < 10)
    {
        cout << '0';
    }
    cout << mm << ':';

    int ss = s % 60;
    if(ss < 10)
    {
        cout << '0';
    }
    cout << ss;

    return 0;
}

T2 数字变换

#include <iostream>
using namespace std;

bool isPrime(int m)
{
    if(m <= 1)
    {
        return false;
    }

    for(int i = 2; i * i <= m; i++)
    {
        if( m % i == 0)
        {
            return false;
        }
    }

    return true;
}

int main()
{
    int n;
    cin >> n;
    if(n == 0 || n == 1)
    {
        cout << 4;
    }
    else if(isPrime(n))
    {
        cout << ((2 == n) ? 4 : n + 1);
    }
    else
    {
        for(int i = 2; i * i <= n; i++)
        {
            if(n % i == 0)
            {
                cout << n / i;
                break;
            }
        }
    }

    return 0;
}

T3 小学生的计算题

#include <iostream>

using namespace std;

int main()
{
    string s;
    cin >> s;
    long  num = 0;
    long long ans = 0;
    for(size_t i = 0; i < s.size(); i++)
    {
        if(s[i] >= '0' && s[i] <= '9')
        {
            num = num * 10 + s[i] - '0';
        }
        else if(s[i] == '+' || s[i] == '=')
        {
            ans += num;
            num = 0;
        }
    }

    cout << s << ans << endl;

    return 0;
}

T4 序列长度

#include <iostream>
using namespace std;

const int MOD = 1000000007;
const int maxN = 10005;
long long f[maxN];

long long fun(int n)
{
    if(f[n])
    {
        return f[n];
    }

    long long cnt = 0;
    for(int i = 1; i <= n/2; i++)
    {
        if(i & 1) //奇数
        {
            int remainder = n % i;
            if(remainder <= 1)
            {
                cnt++;
            }
            else
            {
                //余数大于或等于2需要递归
                cnt += fun(remainder);
            }
        }
        else    //偶数
        {
            //n/i必然大于等于2，所以要递归
            cnt += fun(n / i);
        }
        cnt %= MOD;
    }

    return f[n] = cnt;
}

int main()
{
    int n;
    cin >> n;
    cout << fun(n);
    
    return 0;
}