Add: Excel Sheet Column Number

Author: openset

Diff for: 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 for: 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)
+		}
+	}
+}