charWeight

Given a string s, your task is to calculate the weight of each character in it, where weight is the number of times a character appears in the string (case insensitive).

The answer should be returned as a string in the format char1{weight1}char2{weight2}..., with the characters sorted as follows:

1. The characters with larger weights should come first;
2. In the case of a tie, the characters should be sorted by their char code values in ascending order.

Example:

• For s = "code", the output should be charWeight(s)= "c{1}d{1}e{1}o{1}"

  Each character appears in s exactly once, so the characters are sorted by their char codes.

• For s = "Google", the output should be charWeight(s)= "g{2}o{2}e{1}l{1}"

  The letters 'g' and 'o' both appear twice, so they come first, followed by the other letters.

Input/Output:

• [execution time limit] 0.5 seconds 

• [input] string s

  A string of English letters and digits.
  0 ≤ s.length ≤ 106.

• [output] string

  The weight of each character in the given string, formatted as described above.