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authorDimitri Sokolyuk <demon@dim13.org>2018-03-13 00:55:06 +0100
committerDimitri Sokolyuk <demon@dim13.org>2018-03-13 00:55:06 +0100
commit1d3e4f0944ea1a116da9290ea913de71d54a9778 (patch)
treec70d82a51735c73c6644079ac5c8559a3cf57536
parent58f866493fe786b1e583f7dddf8219ea4f0d5824 (diff)
shrink
-rw-r--r--roman.go24
-rw-r--r--roman_test.go19
2 files changed, 7 insertions, 36 deletions
diff --git a/roman.go b/roman.go
index f57e655..5759992 100644
--- a/roman.go
+++ b/roman.go
@@ -1,35 +1,19 @@
// Package roman numerals
-//
-// For fluff, the unicode overbar is recognized as a factor of 1000.
-//
-// If you see boxes in the code below, those are supposed to be the
-// Unicode combining overline (U+0305) and look like I̅V̅X̅L̅C̅D̅M̅. Or, if
-// you see overstruck combinations of letters, that's a different font
-// rendering problem. (If you need roman numerals > 3999 reliably, it
-// might best to stick to chiseling them in stone...)
-//
-// Source: https://www.rosettacode.org/wiki/Roman_numerals/Encode#Go
package roman
var (
m0 = []string{"", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"}
m1 = []string{"", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"}
m2 = []string{"", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"}
- m3 = []string{"", "M", "MM", "MMM", "I̅V̅", "V̅", "V̅I̅", "V̅I̅I̅", "V̅I̅I̅I̅", "I̅X̅"}
- m4 = []string{"", "X̅", "X̅X̅", "X̅X̅X̅", "X̅L̅", "L̅", "L̅X̅", "L̅X̅X̅", "L̅X̅X̅X̅", "X̅C̅"}
- m5 = []string{"", "C̅", "C̅C̅", "C̅C̅C̅", "C̅D̅", "D̅", "D̅C̅", "D̅C̅C̅", "D̅C̅C̅C̅", "C̅M̅"}
- m6 = []string{"", "M̅", "M̅M̅", "M̅M̅M̅"}
+ m3 = []string{"", "M", "MM", "MMM"}
)
-// Roman represents a roman numeral in interval 0 < x < 4e6
+// Roman numeral in interval 0 < x < 4000
type Roman int
func (n Roman) String() string {
- if n <= 0 || n >= 4e6 {
+ if n <= 0 || n >= 4000 {
return ""
}
- // this is efficient in Go. the seven operands are evaluated,
- // then a single allocation is made of the exact size needed for the result.
- return m6[n/1e6] + m5[n%1e6/1e5] + m4[n%1e5/1e4] + m3[n%1e4/1e3] +
- m2[n%1e3/1e2] + m1[n%1e2/1e1] + m0[n%1e1]
+ return m3[n/1000] + m2[n%1000/100] + m1[n%100/10] + m0[n%10]
}
diff --git a/roman_test.go b/roman_test.go
index 4ad62cf..a61436e 100644
--- a/roman_test.go
+++ b/roman_test.go
@@ -10,25 +10,12 @@ func TestRoman(t *testing.T) {
s string
}{
{0, ""},
- {1, "I"},
- {2, "II"},
- {3, "III"},
- {5, "V"},
- {8, "VIII"},
- {13, "XIII"},
- {21, "XXI"},
- {34, "XXXIV"},
- {55, "LV"},
- {89, "LXXXIX"},
- {100, "C"},
- {200, "CC"},
- {500, "D"},
+ {1990, "MCMXC"},
+ {2008, "MMVIII"},
+ {1666, "MDCLXVI"},
{1e3 - 1, "CMXCIX"},
{2e3 - 1, "MCMXCIX"},
{4e3 - 1, "MMMCMXCIX"},
- {1e6 - 1, "C̅M̅X̅C̅I̅X̅CMXCIX"},
- {2e6 - 1, "M̅C̅M̅X̅C̅I̅X̅CMXCIX"},
- {4e6 - 1, "M̅M̅M̅C̅M̅X̅C̅I̅X̅CMXCIX"},
}
for _, tc := range testCases {
t.Run(tc.s, func(t *testing.T) {