高频题（0）
1. Count Distinct Pairs with Similar Digits
Given an array of numbers, count the number of distinct pairs in the input that have the same number of digits and exactly one different digit. A distinct pair is defined as 0 <= i != j < input.length, and input[i] < input[j]. The input array must satisfy 1 <= input[i] <= 10^9 and 1 <= input.length <= 10^4. Note that a brute force approach will fail 9 hidden cases. For example, given the input array [1, 151, 241, 1, 9, 22, 351], the output should be 3.
2. Convert Snake Case to Camel Case in Substrings
Given a string with special substrings nested in backticks (`), where the special substring contains variables and constants in snake case, with constants being in all caps (e.g., THIS_IS_A_CONSTANT), output a string with variables converted from snake case to camel case. For example, the input 'hi there `this_is_a_variable another_variable_` eheh `THIS_IS_A_CONSTANT` ' should be transformed to 'hi there `thisIsAVariable anotherVariable` eheh `THIS_IS_A_CONSTANT` '.
3. Student with Highest Average Grade
Given an array of strings in the format 'student: grade', where all students have unique names, determine the name of the student with the highest average grade. For example, given ['max: 100', 'toby: 100', 'max:95'], the output should be 'toby' since Max's average is (100+95)/2 = 97.5, and Toby's average is 100/1 = 100.
4. Array Transformation Based on Characters
Given an array of strings, transform the array such that every index i in the resulting array equals the first character of index i of the input array concatenated with the last character of the next index (i+1) of the input array. When i is the last index of the input array, the next index is considered to be 0.
5. Valid Pair Count in Array
Given an array, count all valid pairs where two numbers are of the same length and one number can become the other by changing just one digit. For example, given the array {1, 151, 241, 1, 9, 22, 351}, return 3 for the valid pairs: <1, 9>, <1, 9>, <151, 351>.
