From c574f3a505d9515e8988b78ddd2f410f0bbad190 Mon Sep 17 00:00:00 2001
From: Openset <openset.wang@gmail.com>
Date: Sun, 30 Dec 2018 14:04:07 +0800
Subject: [PATCH] Add: integer_to_roman

---
 problems/integer-to-roman/integer_to_roman.go | 13 +++++
 .../integer-to-roman/integer_to_roman_test.go | 52 +++++++++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/problems/integer-to-roman/integer_to_roman.go b/problems/integer-to-roman/integer_to_roman.go
index 4b828f21e..55ba3625d 100644
--- a/problems/integer-to-roman/integer_to_roman.go
+++ b/problems/integer-to-roman/integer_to_roman.go
@@ -1 +1,14 @@
 package integer_to_roman
+
+func intToRoman(num int) string {
+	base := [...]int{1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1}
+	bs := [...]string{"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"}
+	ans := ""
+	for i, b := range base {
+		for num/b > 0 {
+			ans += bs[i]
+			num -= b
+		}
+	}
+	return ans
+}
diff --git a/problems/integer-to-roman/integer_to_roman_test.go b/problems/integer-to-roman/integer_to_roman_test.go
index 4b828f21e..a68b06494 100644
--- a/problems/integer-to-roman/integer_to_roman_test.go
+++ b/problems/integer-to-roman/integer_to_roman_test.go
@@ -1 +1,53 @@
 package integer_to_roman
+
+import "testing"
+
+type caseType struct {
+	input    int
+	expected string
+}
+
+func TestIntToRoman(t *testing.T) {
+	tests := [...]caseType{
+		{
+			input:    3,
+			expected: "III",
+		},
+		{
+			input:    4,
+			expected: "IV",
+		},
+		{
+			input:    9,
+			expected: "IX",
+		},
+		{
+			input:    20,
+			expected: "XX",
+		},
+		{
+			input:    58,
+			expected: "LVIII",
+		},
+		{
+			input:    1994,
+			expected: "MCMXCIV",
+		},
+		{
+			input:    11111,
+			expected: "MMMMMMMMMMMCXI",
+		},
+	}
+	for _, tc := range tests {
+		output := intToRoman(tc.input)
+		if output != tc.expected {
+			t.Fatalf("input: %v, output: %v, expected: %v", tc.input, output, tc.expected)
+		}
+	}
+}
+
+func BenchmarkIntToRoman(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		intToRoman(111111)
+	}
+}