2.2 preface

好久没做题了，坚持！

Preface Numbering

A certain book's prefaces are numbered in upper case Roman numerals.Traditional Roman numeral values use a single letter to represent acertain subset of decimal numbers. Here is the standard set:

        I   1     L   50    M  1000
        V   5     C  100
        X  10     D  500

As many as three of the same marks that represent 10ⁿmay be placed consecutively to form other numbers:

• III is 3
• CCC is 300

Marks that have the value 5x10ⁿ are never used consecutively.

Generally (with the exception of the next rule), marks are connectedtogether and written in descending order to form even more numbers:

CCLXVIII = 100+100+50+10+5+1+1+1 = 268

Sometimes, a mark that represents 10^n is placed before a mark ofone of the two next higher values (I before V or X; X before L or C;etc.). In this case, the value of the smaller mark is SUBTRACTED fromthe mark it precedes:

• IV = 4
• IX = 9
• XL = 40

This compound mark forms a unit and may not be combined to makeanother compound mark (e.g., IXL is wrong for 39; XXXIX is correct).

Compound marks like XD, IC, and XM are not legal, since thesmaller mark is too much smaller than the larger one. For XD (wrongfor 490), one would use CDXC; for IC (wrong for 99), one would useXCIX; for XM (wrong for 990), one would use CMXC. 90 is expressedXC and not LXL, since L followed by X connotes that successive marksare X or smaller (probably, anyway).

Given N (1 <= N < 3,500), the number of pages in thepreface of a book, calculate and print the number of I's, V's, etc. (inorder from lowest to highest) required to typeset all the page numbers(in Roman numerals) from 1 through N. Do not print letters that do notappear in the page numbers specified.

If N = 5, then the page numbers are: I, II, III, IV, V. The totalnumber of I's is 7 and the total number of V's is 2.

PROGRAM NAME: preface

INPUT FORMAT

A single line containing the integer N.

SAMPLE INPUT (file preface.in)

5

OUTPUT FORMAT

The output lines specify, in ascending order of Roman numeral letters,the letter, a single space, and the number of times that letter appearson preface page numbers. Stop printing letter totals after printingthe highest value letter used to form preface numbers in the specifiedset.

SAMPLE OUTPUT (file preface.out)

I 7
V 2

/*ID: xdzhbin1LANG: C++TASK:preface*///有点意外，编码结束后，都没有测，直接提交，竟然一次通过了，很高兴//简单统计，统计用罗马数字表示一个序列的数字，各需要多少个字符#include <iostream>#include <fstream>using namespace std;class Counter{    private:    int start,end;  //统计开始和结束的数字    char letters[4][2];//存放罗马字符    int result[4][2]; //统计结果    void deal(int num); //对一个具体的数字统计    public:    Counter();    void statistic();   //统计    void display();     //显示};Counter::Counter(){    ifstream in("preface.in",ios::in);    start = 1;    in>>end;    //读入序列终点    in.close();    letters = {{'I','V'}, // 1 5    {'X','L'},  //10 50    {'C','D'},  //100 500    {'M','N'}   //1000 5000    };    int i,j;    for(i=0; i<4; i++)    {        for(j=0; j<2; j++)        {            result[i][j] = 0;        }    }}void Counter::statistic(){    int i;    for(i=start; i<=end; i++)    {        deal(i);    }}void Counter::deal(int num){    int index = 0;    int temp;    //从个位开始统计，index标识是个位还是十位、百位还是千位    while(num != 0)    {        temp = num % 10;        if(temp>=0 && temp<=3)        {            result[index][0] += temp;        }        else if(temp == 4)        {            result[index][0]++;            result[index][1]++;        }        else if(temp>=5 && temp<=8)        {            result[index][1]++;            result[index][0] += (temp - 5);        }        else        {            result[index][0]++;            result[index+1][0]++;        }        index++;        num /= 10;    }}void Counter::display(){    ofstream out("preface.out",ios::out);    int i,j;    for(i=0; i<4; i++)    {        for(j=0; j<2; j++)        {            if(result[i][j] != 0)            {                out<<letters[i][j]<<" "<<result[i][j]<<endl;            }        }    }    out.close();}int main(){    Counter c;    c.statistic();    c.display();    return 0;}