Leetcode

Excel Sheet Column Number

  • Time:O(n)
  • Space:O(1)

C++

class Solution {
 public:
  int titleToNumber(string s) {
    return accumulate(begin(s), end(s), 0,
                      [](int a, int b) { return a * 26 + (b - 'A' + 1); });
  }
};

JAVA

class Solution {
  public int titleToNumber(String s) {
    int ans = 0;

    for (final char c : s.toCharArray())
      ans = ans * 26 + c - '@';

    return ans;
  }
}

Python

class Solution:
  def titleToNumber(self, s: str) -> int:
    ans = 0

    for c in s:
      ans = ans * 26 + ord(c) - ord('@')

    return ans