將一個數轉換成羅馬數字，然后統計各個字母的個數。
羅馬字母可以由兩個字母組合而成，把這些字母手工生成放在一個表中稱之為cell，然后每次減去一個
小于自身的最大的cell直到為0為止。
#include?<iostream>
#include?<fstream>
#include?<vector>
#include?<string>
using?namespace?std;
ifstream?fin("preface.in");
ofstream?fout("preface.out");
#ifdef?_DEBUG
#define?out?cout
#define?in?cin
#else
#define?out?fout
#define?in?fin
#endif
//code[i]為i的各個字母的個數
int?code[3501][7];
bool?visited[3501];
int?result[7];
//最初的字母表
char?alpha[]?=?{?'I','V','X','L','C','D','M'};
//cell表
char*?cell[13]?=?{"I","IV","V","IX","X","XL","L","XC","C","CD","D","CM","M"};
//cell表對應的值
int?cell_value[13]?=?{1,4,5,9,10,40,50,90,100,400,500,900,1000};
//字母c在alpha表中的索引值
int?get_num(char?c)
{
????for(int?i=0;i<sizeof(alpha)/sizeof(char);++i)
????????if(alpha[i]==c)?return?i;
????return?-1;
}
//第一個小于n的cell的索引
int?find_first_smaller(int?n)
{
????for(int?i=12;i>=0;--i){
????????if(cell_value[i]<=n)?return?i;
????}
}
void?solve()
{
????for(int?i=0;i<13;++i){
????????visited[cell_value[i]]=true;
????????char?*tmp?=?cell[i];
????????while(*tmp!=0){
????????????code[cell_value[i]][get_num(*tmp)]++;
????????????tmp++;
????????}
????}
????int?n;
????in>>n;
????for(int?i=1;i<=n;++i){
????????if(visited[i]){
????????????for(int?j=0;j<7;++j){
????????????????result[j]+=code[i][j];
????????????}
????????}else{
????????????int?tmp?=?i;
????????????while(tmp!=0&&!visited[tmp]){
????????????????int?t?=?find_first_smaller(tmp);
????????????????for(int?j=0;j<7;++j){
????????????????????code[i][j]+=code[cell_value[t]][j];
????????????????}
????????????????tmp-=cell_value[t];
????????????}
????????????if(tmp!=0){
????????????????for(int?j=0;j<7;++j)
????????????????????code[i][j]+=code[tmp][j];
????????????}
????????????for(int?j=0;j<7;++j)
????????????????result[j]+=code[i][j];
????????????visited[i]?=?true;
????????}
????}
????for(int?i=0;i<7;++i){
????????if(result[i]!=0){
????????????out<<alpha[i]<<"?"<<result[i]<<endl;
????????}
????}
}
int?main(int?argc,char?*argv[])
{
????solve();?
????return?0;
}