Solve problem '171) excel sheet column number'

Author: ozantopal

problems/171-excel-sheet-column-number/README.md

@@ -0,0 +1,41 @@
+Given a string **columnTitle** that represents the column title as appear in an Excel sheet, return _its corresponding column number_.
+
+For example:
+
+```
+A -> 1
+B -> 2
+C -> 3
+...
+Z -> 26
+AA -> 27
+AB -> 28
+...
+```
+
+**Example 1:**
+
+```
+Input: columnTitle = "A"
+Output: 1
+```
+
+**Example 2:**
+
+```
+Input: columnTitle = "AB"
+Output: 28
+```
+
+**Example 3:**
+
+```
+Input: columnTitle = "ZY"
+Output: 701
+```
+
+**Constraints:**
+
+- `1 <= columnTitle.length <= 7`
+- `columnTitle` consists only of uppercase English letters.
+- `columnTitle` is in the range `["A", "FXSHRXW"]`.

problems/171-excel-sheet-column-number/main.go

@@ -0,0 +1,19 @@
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println(titleToNumber("A"))
+	fmt.Println(titleToNumber("AB"))
+	fmt.Println(titleToNumber("ZY"))
+}
+
+func titleToNumber(columnTitle string) int {
+	result, val := 0, 0
+	for i := 0; i < len(columnTitle); i++ {
+		val = int(columnTitle[i] - 'A' + 1)
+		result = result*26 + val
+	}
+
+	return result
+}