p1465 Preface Numbering

用这个函数转成罗马数字统计就行了。

#include <iostream>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cstring>
#include <map>
#include <queue>
#include <set>
#include <cassert>
#include <stack>
#define mkp make_pair
using namespace std;
const double EPS=1e-8;
typedef long long lon;
const lon SZ=30,INF=0x7FFFFFFF;

string intToRoman(int num) {
        string c[4][10]={
            {"","I","II","III","IV","V","VI","VII","VIII","IX"},
            {"","X","XX","XXX","XL","L","LX","LXX","LXXX","XC"},
            {"","C","CC","CCC","CD","D","DC","DCC","DCCC","CM"},
            {"","M","MM","MMM"}};
        string roman;
        roman.append(c[3][num / 1000 % 10]);
        roman.append(c[2][num / 100 % 10]);
        roman.append(c[1][num / 10 % 10]);
        roman.append(c[0][num % 10]);
         
        return roman;
    }

int main()
{
    std::ios::sync_with_stdio(0);
    //freopen("d:\\1.txt","r",stdin);
    lon casenum;
    //cin>>casenum;
    //for(lon time=1;time<=casenum;++time)
    {
        int n;
        cin>>n;
        map<char,int> mp;
        for(int i=1;i<=n;++i)
        {
            string tmp=intToRoman(i);
            for(int j=0;j<tmp.size();++j)
            {
                ++mp[tmp[j]];
            }
        }
        if(mp['I'])cout<<'I'<<" "<<mp['I']<<endl;
        if(mp['V'])cout<<'V'<<" "<<mp['V']<<endl;
        if(mp['X'])cout<<'X'<<" "<<mp['X']<<endl;
        if(mp['L'])cout<<'L'<<" "<<mp['L']<<endl;
        if(mp['C'])cout<<'C'<<" "<<mp['C']<<endl;
        if(mp['D'])cout<<'D'<<" "<<mp['D']<<endl;
        if(mp['M'])cout<<'M'<<" "<<mp['M']<<endl;
    }
    return 0;
}

string intToRoman(int num) {
string c[4][10]={
{"","I","II","III","IV","V","VI","VII","VIII","IX"},
{"","X","XX","XXX","XL","L","LX","LXX","LXXX","XC"},
{"","C","CC","CCC","CD","D","DC","DCC","DCCC","CM"},
{"","M","MM","MMM"}};
string roman;
roman.append(c[3][num / 1000 % 10]);
roman.append(c[2][num / 100 % 10]);
roman.append(c[1][num / 10 % 10]);
roman.append(c[0][num % 10]);

return roman;
}