We Got Everything Covered! (Codeforces 1925A)
Tags: Greedy, strings

You are given two positive integers $$$n$$$ and $$$k$$$. Your task is to find a string $$$s$$$ such that all possible strings of length $$$n$$$ that can be formed using the first $$$k$$$ lowercase English alphabets occur as a subsequence of $$$s$$$. If there are multiple answers, print the one with the smallest length. If there are still multiple answers, you may print any of them.Note: A string $$$a$$$ is called a subsequence of another string $$$b$$$ if $$$a$$$ can be obtained by deleting some (possibly zero) characters from $$$b$$$ without changing the order of the remaining characters.

Input: The first line of input contains a single integer $$$t$$$ ($$$1\leq t\leq 676$$$) denoting the number of test cases.Each test case consists of a single line of input containing two integers $$$n$$$ ($$$1\leq n\leq 26$$$) and $$$k$$$ ($$$1\leq k\leq 26$$$).

Output: For each test case, print a single line containing a single string $$$s$$$ which satisfies the above property. If there are multiple answers, print the one with the smallest length. If there are still multiple answers, you may print any of them.

Note: For the first test case, there are two strings of length $$$1$$$ which can be formed using the first $$$2$$$ lowercase English alphabets, and they are present in $$$s$$$ as a subsequence as follows:   $$$\texttt{a}: {\color{red}{\texttt{a}}}\texttt{b}$$$  $$$\texttt{b}: \texttt{a}{\color{red}{\texttt{b}}}$$$ For the second test case, there is only one string of length $$$2$$$ which can be formed using the first lowercase English alphabet, and it is present in $$$s$$$ as a subsequence as follows:   $$$\texttt{aa}: {\color{red}{\texttt{aa}}}$$$ For the third test case, there are $$$4$$$ strings of length $$$2$$$ which can be formed using the first $$$2$$$ lowercase English alphabets, and they are present in $$$s$$$ as a subsequence as follows:   $$$\texttt{aa}: \texttt{b}{\color{red}{\texttt{aa}}}\texttt{b}$$$  $$$\texttt{ab}: \texttt{ba}{\color{red}{\texttt{ab}}}$$$  $$$\texttt{ba}: {\color{red}{\texttt{ba}}}\texttt{ab}$$$  $$$\texttt{bb}: {\color{red}{\texttt{b}}}\texttt{aa}{\color{red}{\texttt{b}}}$$$ For the fourth test case, there are $$$9$$$ strings of length $$$2$$$ which can be formed using the first $$$3$$$ lowercase English alphabets, and they are present in $$$s$$$ as a subsequence as follows:   $$$\texttt{aa}: {\color{red}{\texttt{a}}}\texttt{bcb}{\color{red}{\texttt{a}}}\texttt{c}$$$  $$$\texttt{ab}: {\color{red}{\texttt{ab}}}\texttt{cbac}$$$  $$$\texttt{ac}: \texttt{abcb}{\color{red}{\texttt{ac}}}$$$  $$$\texttt{ba}: \texttt{abc}{\color{red}{\texttt{ba}}}\texttt{c}$$$  $$$\texttt{bb}: \texttt{a}{\color{red}{\texttt{b}}}\texttt{c}{\color{red}{\texttt{b}}}\texttt{ac}$$$  $$$\texttt{bc}: \texttt{a}{\color{red}{\texttt{bc}}}\texttt{bac}$$$  $$$\texttt{ca}: \texttt{ab}{\color{red}{\texttt{c}}}\texttt{b}{\color{red}{\texttt{a}}}\texttt{c}$$$  $$$\texttt{cb}: \texttt{ab}{\color{red}{\texttt{cb}}}\texttt{ac}$$$  $$$\texttt{cc}: \texttt{ab}{\color{red}{\texttt{c}}}\texttt{ba}{\color{red}{\texttt{c}}}$$$ 

Sample Inputs:
4
1 2
2 1
2 2
2 3

Sample Outputs:
ab
aa
baab
abcbac

Solution (Python):
s = 'abcdefghijklmnopqrstuvwxyz'
for i in range(int(input())):
    (n, k) = map(int, input().split())
    print(s[0:k] * n)

Solution (Python):
t = int(input())
F = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']
for i in range(t):
    (n, k) = map(int, input().split())
    print(''.join(F[0:k]) * n)

Solution (Python):
for _ in range(int(input())):
    (n, k) = map(int, input().split())
    b = 'abcdefghijklmnopqrstuvwxyz'
    print(str(b[:k]) * n)