Leetcode | | Integer to Roman problem

Problem:

Given an integer, convert it to a Roman numeral. Input is guaranteed to being within the range from 1 to 3999.

Converts an integer of 1-3999 to Roman numerals

Thinking:

(1)

Contrast example

Single Digit Example
ⅰ,1 "ⅱ,2" ⅲ,3 "ⅳ,4" ⅴ,5 "ⅵ,6" ⅶ,7 "ⅷ,8" ⅸ,9 "
Example of 10 digits
ⅹ,10 "ⅺ,11" ⅻ,12 "xiii,13" xiv,14 "xv,15" xvi,16 "xvii,17" xviii,18 "xix,19" xx,20 "xxi,21" xxii,22 "XXIX,29" XXX,30 "XXXI V,34 "xxxv,35" xxxix,39 "xl,40" l,50 "li,51" lv,55 "lx,60" lxv,65 "lxxx,80" xc,90 "xciii,93" xcv,95 "XCVIII,98" XCIX,99 "
Examples of hundred
c,100 "cc,200" ccc,300 "cd,400" d,500 "dc,600" dcc,700 "dccc,800" cm,900 "cmxcix,999"
Thousands of examples
m,1000 "mc,1100" mcd,1400 "md,1500" mdc,1600 "mdclxvi,1666" mdccclxxxviii,1888 "mdcccxcix,1899" MCM,1900 "MCMLXXVI,1976 "mcmlxxxiv,1984" mcmxc,1990 "mm,2000" mmmcmxcix,3999 "

(2) The technique of avoiding N-Multi-conditional judgment: Using the law of Roman numerals and subtracting a cardinal number to simplify the complexity

Code

Class Solution {public:    string inttoroman (int num)    {        int values[] = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1};        String numerals[] = {"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"};        string result;        for (int i = 0, I < i++) {while            (num >= values[i]) {num-                = values[i];                Result.append (Numerals[i]);            }        }        return result;}    ;

Leetcode | | Integer to Roman problem