1+ package leetcode .editor .en ;
2+ 3+ import java .util .*;
4+ 5+ class RomanToInteger {
6+ 7+ //leetcode submit region begin(Prohibit modification and deletion)
8+ class Solution {
9+ public int romanToInt (String s ) {
10+ int start = 0 , out = 0 ;
11+ RomanDigit [][] ordersOfMagnitude = new RomanDigit [][]{
12+ RomanDigit .THOUSANDS , RomanDigit .HUNDREDS , RomanDigit .TENS , RomanDigit .ONES
13+ };
14+ for (RomanDigit [] choices : ordersOfMagnitude ) {
15+ for (RomanDigit digit : choices ) {
16+ if (digit .text .equals (safeSubstring (s , start , start + digit .length ))) {
17+ out += digit .value ;
18+ start += digit .length ;
19+ break ;
20+ }
21+ }
22+ }
23+ return out ;
24+ }
25+ private String safeSubstring (String s , int start , int end ){
26+ if (end > s .length ()) return null ;
27+ return s .substring (start , end );
28+ }
29+ private record RomanDigit (
30+ String text ,
31+ int length ,
32+ int value
33+ ){
34+ final static RomanDigit [] ONES = new RomanDigit []{
35+ new RomanDigit ("III" , 3 , 3 ),
36+ new RomanDigit ("II" , 2 , 2 ),
37+ new RomanDigit ("IV" , 2 , 4 ),
38+ new RomanDigit ("IX" , 2 , 9 ),
39+ new RomanDigit ("VIII" , 4 , 8 ),
40+ new RomanDigit ("VII" , 3 , 7 ),
41+ new RomanDigit ("VI" , 2 , 6 ),
42+ new RomanDigit ("V" , 1 , 5 ),
43+ new RomanDigit ("I" , 1 , 1 )
44+ };
45+ final static RomanDigit [] TENS = new RomanDigit []{
46+ new RomanDigit ("XXX" , 3 , 30 ),
47+ new RomanDigit ("XX" , 2 , 20 ),
48+ new RomanDigit ("XC" , 2 , 90 ),
49+ new RomanDigit ("XL" , 2 , 40 ),
50+ new RomanDigit ("LXXX" , 4 , 80 ),
51+ new RomanDigit ("LXX" , 3 , 70 ),
52+ new RomanDigit ("LX" , 2 , 60 ),
53+ new RomanDigit ("L" , 1 , 50 ),
54+ new RomanDigit ("X" , 1 , 10 )
55+ };
56+ final static RomanDigit [] HUNDREDS = new RomanDigit []{
57+ new RomanDigit ("CCC" , 3 , 300 ),
58+ new RomanDigit ("CC" , 2 , 200 ),
59+ new RomanDigit ("CM" , 2 , 900 ),
60+ new RomanDigit ("CD" , 2 , 400 ),
61+ new RomanDigit ("DCCC" , 4 , 800 ),
62+ new RomanDigit ("DCC" , 3 , 700 ),
63+ new RomanDigit ("DC" , 2 , 600 ),
64+ new RomanDigit ("D" , 1 , 500 ),
65+ new RomanDigit ("C" , 1 , 100 )
66+ };
67+ final static RomanDigit [] THOUSANDS = new RomanDigit []{
68+ new RomanDigit ("MMM" , 3 , 3000 ),
69+ new RomanDigit ("MM" , 2 , 2000 ),
70+ new RomanDigit ("M" , 1 , 1000 )
71+ };
72+ 73+ }
74+ }
75+ //leetcode submit region end(Prohibit modification and deletion)
76+ 77+ }
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