Write a function that accepts msg string and returns local tops of string from the highest to the lowest. The string's tops are from displaying the string in the below way:
3
p 2 4
g o q 1
b f h n r z a c e i m s y d j l t x k u w v
The next top is always 1 character higher than the previous one. For the above example, the solution for the abcdefghijklmnopqrstuvwxyz1234 input string is 3pgb.
- When the msg string is empty, return an empty string.
- The input strings may be very long. Make sure your solution has good performance.
Check the test cases for more samples. Note for C++
Do not post an issue in my solution without checking if your returned string doesn't have some invisible characters.
You read most probably outside of msg string.