计数问题+约瑟夫问题(map)

一、计数问题

#include<iostream>
#include<map>
using namespace std;
int main()
{
    int n,x;
    cin>>n>>x;
    map<int,int>m;
    for(int i=1;i<=n;i++)
    {
        if(i>=1 && i<10)
        {
            m[i]++;
        }
        else
        {
           int temp = i;
            while (temp > 0)
            {
                int digit = temp % 10;
                m[digit]++;
                temp /= 10;
            }
        }
    }
    
    cout<<m[x];
    return 0;
}

 二、约瑟夫问题

#include<iostream>
#include<map>
using namespace std;
int main()
{
    int n, k, m;
    cin >> n >> k >> m;
    map<int, int>_map;
    for (int i = 0; i < n; i++)
    {
        _map[i]++;
    }

    int start = k;
    int count = 0;
    int total = n;
    while (total != 1)
    {
        if (_map[start] == 1)
        {
            count++;
            if (count == m)
            {
                _map[start] = 0;
                --total;
                count = 0;
            }
        }
        start = (start + 1) % n;
    }

    map<int, int>::iterator it = _map.begin();
    while (it != _map.end())
    {
        if (it->second == 1)
        {
            cout << it->first;
            return 0;
        }
        ++it;
    }
}