2194. Cells in a Range on an Excel Sheet

A cell (r, c) of an excel sheet is represented as a string ““ where:

• denotes the column number c of the cell. It is represented by alphabetical letters.

• For example, the 1st column is denoted by ‘A’, the 2nd by ‘B’, the 3rd by ‘C’, and so on.

• is the row number r of the cell. The rth row is represented by the integer r.

You are given a string s in the format “:“, where represents the column c1, represents the row r1, represents the column c2, and represents the row r2, such that r1 <= r2 and c1 <= c2.

Return the list of cells (x, y) such that r1 <= x <= r2 and c1 <= y <= c2. The cells should be represented as strings in the format mentioned above and be sorted in non-decreasing order first by columns and then by rows.

class Solution {
public:
    vector<string> cellsInRange(string s) {
        char r1 = s[0], r2 = s[3];
        char c1 = s[1], c2 = s[4];
        vector<string> res;
        for(char row = r1; row <= r2; row++) {
            for(char col = c1; col <= c2; col++) {
                string tmp = string(1,row) + string(1,col);
                res.push_back(tmp);
            }
        }
        return res;
    }
};