From a581d27d24581394300e316f636d9ff5e5c480a4 Mon Sep 17 00:00:00 2001
From: openset <openset@users.noreply.github.com>
Date: Tue, 26 Feb 2019 11:06:36 +0800
Subject: [PATCH] Add: Excel Sheet Column Number

---
 .../excel_sheet_column_number.go              |  9 ++++
 .../excel_sheet_column_number_test.go         | 49 +++++++++++++++++++
 2 files changed, 58 insertions(+)

diff --git a/problems/excel-sheet-column-number/excel_sheet_column_number.go b/problems/excel-sheet-column-number/excel_sheet_column_number.go
index 98817f5c9..6061154dc 100644
--- a/problems/excel-sheet-column-number/excel_sheet_column_number.go
+++ b/problems/excel-sheet-column-number/excel_sheet_column_number.go
@@ -1 +1,10 @@
 package excel_sheet_column_number
+
+func titleToNumber(s string) int {
+	ans := 0
+	for _, c := range s {
+		ans *= 26
+		ans += int(c) - 'A' + 1
+	}
+	return ans
+}
diff --git a/problems/excel-sheet-column-number/excel_sheet_column_number_test.go b/problems/excel-sheet-column-number/excel_sheet_column_number_test.go
index 98817f5c9..476dd0228 100644
--- a/problems/excel-sheet-column-number/excel_sheet_column_number_test.go
+++ b/problems/excel-sheet-column-number/excel_sheet_column_number_test.go
@@ -1 +1,50 @@
 package excel_sheet_column_number
+
+import "testing"
+
+type caseType struct {
+	input    string
+	expected int
+}
+
+func TestTitleToNumber(t *testing.T) {
+	tests := [...]caseType{
+		{
+			input:    "A",
+			expected: 1,
+		},
+		{
+			input:    "C",
+			expected: 3,
+		},
+		{
+			input:    "Z",
+			expected: 26,
+		},
+		{
+			input:    "AA",
+			expected: 27,
+		},
+		{
+			input:    "AB",
+			expected: 28,
+		},
+		{
+			input:    "ZY",
+			expected: 701,
+		}, {
+			input:    "AAA",
+			expected: 703,
+		},
+		{
+			input:    "XYZ",
+			expected: 16900,
+		},
+	}
+	for _, tc := range tests {
+		output := titleToNumber(tc.input)
+		if output != tc.expected {
+			t.Fatalf("input: %v, output: %v, expected: %v", tc.input, output, tc.expected)
+		}
+	}
+}