leetcode171

public class Solution {
    private int ConvertToC(char c)
        {
            int rnt = ;

            switch (c)
            {
                case 'A':
                case 'a':
                    rnt = ;
                    break;
                case 'B':
                case 'b':
                    rnt = ;
                    break;
                case 'C':
                case 'c':
                    rnt = ;
                    break;
                case 'D':
                case 'd':
                    rnt = ;
                    break;
                case 'E':
                case 'e':
                    rnt = ;
                    break;
                case 'F':
                case 'f':
                    rnt = ;
                    break;
                case 'G':
                case 'g':
                    rnt = ;
                    break;
                case 'H':
                case 'h':
                    rnt = ;
                    break;
                case 'I':
                case 'i':
                    rnt = ;
                    break;
                case 'J':
                case 'j':
                    rnt = ;
                    break;
                case 'K':
                case 'k':
                    rnt = ;
                    break;
                case 'L':
                case 'l':
                    rnt = ;
                    break;
                case 'M':
                case 'm':
                    rnt = ;
                    break;
                case 'N':
                case 'n':
                    rnt = ;
                    break;
                case 'O':
                case 'o':
                    rnt = ;
                    break;
                case 'P':
                case 'p':
                    rnt = ;
                    break;
                case 'Q':
                case 'q':
                    rnt = ;
                    break;
                case 'R':
                case 'r':
                    rnt = ;
                    break;
                case 'S':
                case 's':
                    rnt = ;
                    break;
                case 'T':
                case 't':
                    rnt = ;
                    break;
                case 'U':
                case 'u':
                    rnt = ;
                    break;
                case 'V':
                case 'v':
                    rnt = ;
                    break;
                case 'W':
                case 'w':
                    rnt = ;
                    break;
                case 'X':
                case 'x':
                    rnt = ;
                    break;
                case 'Y':
                case 'y':
                    rnt = ;
                    break;
                case 'Z':
                case 'z':
                    rnt = ;
                    break;
                default:
                    rnt = ;
                    break;
            }
            return rnt;
        }

        public int TitleToNumber(string s)
        {
            var list = s.ToList();
            var count = list.Count;

            int sum = ;

            for (int i = ; i < list.Count; i++)
            {
                var mi = count - i - ;
                //mi是幂  * pow(26,mi)
                int num = ConvertToC(list[i]);
                sum += num * Convert.ToInt32(Math.Pow(, mi));
            }

            Console.WriteLine(sum);
            return sum;
        }
}

https://leetcode.com/problems/excel-sheet-column-number/#/description

补充一个python的实现：

 class Solution:
     def titleToNumber(self, s: 'str') -> 'int':
         s = s.upper()
         n = len(s)
         sums =
         k =
         for i in range(n-,-,-):
             asci = ord(s[i]) -
             sums +=  ** k * asci
             k +=
         return sums