Reverse Words in a String with Original Position Maintenance

Problem Description Given a string, you need to reverse the words but keep the position of non-letter characters unchanged. For example, given the input string "a red, a work:", the output should be "work a, red a:". Here, the position of letters and commas remain unchanged. Input A string containing multiple words and possible punctuation marks. It is guaranteed that it contains at least one letter character. Output A string with reversed words but with the positions of non-letter characters unchanged. Test Cases Input: "a red, a work:" Output: "work a, red a:" Input: "Hello, World!" Output: "World, Hello!" Input: "This is a test." Output: "test is a This." Input: "No, it is not." Output: "not, it is No." Input: "Single-word!" Output: "Single-word!" Example Input a red, a work: