12. How many different strings can be made from the letters in AARDVARK, using all the letters, a) with no restrictions? b) if all three A's must be consecutive?

Write a routine ungets(s) that will push back an entire string onto the input.Should ungets know about buf and bufp, or should it just use ungetch?

Write a regular expression that defines strings that have an even (but nonzero) number of "a" characters followed by an odd number of "b" characters. For example, aab, aabbb, aaaab, and aaaabbb should all match the regular expression.

2. Give a regular expression for the set of all strings on the alphabet {a, b} with no runs of length greater than 3 (ie. no substrings a or b with j > 3).

write a program that uses a for loop. You’ll need to be able to explain it (not just send the code). In particular, explain how the loop works, and how the different forms of loop (for, for/list, for/vector, etc) are different from one another (this will require some experimentation to find out what each one does). Using racket

Correct answer will be upvoted else Multiple Downvoted. Don't submit random answer. Computer science.     A string b is an aftereffect of a string an if b can be gotten from a by cancellation of a few (conceivably, zero or all) characters. For instance, "xy" is an aftereffect of "xzyw" and "xy", yet not    You are given a string a. Your errand is to reorder the characters of a so that "trygub" isn't an aftereffect of the subsequent string   All in all, you should find a string b which is a stage of images of the string an and "trygub" isn't an aftereffect of b   We have a genuinely superb confirmation that any string can be sorted out not to contain "trygub" as an aftereffect, however this issue explanation is too short to even think about containing it   Inpu   The primary line contains a solitary integer t (1≤t≤100) — the number of experiments   The primary line of each experiment contains a solitary integer n (1≤n≤200) — the length of a   The following line contains the string an of…

A lapindrome is defined as a string that, when split in the middle, gives two halves with the same characters and the same frequency of each character. If there is an odd number of characters in the string, we ignore the middle character and check the lapindrome. For example, gaga is a lapindrome because the two halves of ga and ga have the same characters with the same frequency. Also abccab, rotor and xyzzy are some examples of lapindromes. Note that abbaab is NOT a lapindrome. Both halves contain the same characters, but their frequencies do not match. Your task is simple. You have to figure out if it's a lapindrome by looking at the string. Note: Please Answer in Python Only Input 1 gaga Output YES

You can check whether a string is a substring of another string by using the find method in the str class. Write your own function to implementfind. Write a program that prompts the user to enter two strings and then checks whether the first string is a substring of the second string.

Implement a mechanism for performing basic string compression using repeated character counts. The string aabccccaaa, for example, would become a2blc5a3. Your method should return the original string if the "compressed" string does not grow smaller than the original string. You can assume that the string only contains uppercase and lowercase letters (a-z).