Add: Excel Sheet Column Title

Author: openset

problems/excel-sheet-column-title/excel_sheet_column_title.go

@@ -1,8 +1,19 @@
-package excel_sheet_column_title
+package problem_168
 
+// Solution 1: recursive
 func convertToTitle(n int) string {
 	if n--; n < 26 {
 		return string(n + 'A')
 	}
 	return convertToTitle(n/26) + string(n%26+'A')
 }
+
+// Solution 2: iteration
+func convertToTitle2(n int) string {
+	ans := ""
+	for ; n > 0; n /= 26 {
+		n--
+		ans = string(n%26+'A') + ans
+	}
+	return ans
+}

problems/excel-sheet-column-title/excel_sheet_column_title_test.go

@@ -1,4 +1,4 @@
-package excel_sheet_column_title
+package problem_168
 
 import "testing"
 
@@ -46,10 +46,18 @@ func TestConvertToTitle(t *testing.T) {
 			expected: "XYZ",
 		},
 	}
+	// Solution 1
 	for _, tc := range tests {
 		output := convertToTitle(tc.input)
 		if output != tc.expected {
 			t.Fatalf("input: %v, output: %v, expected: %v", tc.input, output, tc.expected)
 		}
 	}
+	// Solution 2
+	for _, tc := range tests {
+		output := convertToTitle2(tc.input)
+		if output != tc.expected {
+			t.Fatalf("input: %v, output: %v, expected: %v", tc.input, output, tc.expected)
+		}
+	}
 }