Problem 1:

You are given an array consisting of n integers. You are given q queries. Each query has two integers x and m. for each query, you are required to determine the array value that provides the maximum bitwise XOR value with x where the array value is not more than m.

In other words, for each query, you must find arr[i] (1<=i<=n , arr[i]<=m) such that the value of (x ^ arr[i]) is maximum where ^ denotes bitwise XOR operator. If there is no such value that satisfies the condition, then print -1.

Input Format:

• first line contains an integer t denoting the number of test cases.
• first line of each test case contains an integer n denoting the number of elements in the array.
• second line of each test case contains n space-separated integers denoting arr[1],arr[2],.....,arr[n].
• third line of each test case contains an integer q denoting the number of queries.
• next q lines contain two integers x and m denoting the ith query.

Output Format:

• For each test case, print q space-separated integers denoting the required answer.

Constraints:

• 1<=t<=5
• 1<=n,q<=10^5
• 0<=arr[i],x,m<=10^9

Problem 2:

You are given a matrix A of size N*N. Assign the letter 'a' and ID 1,'b' and ID 2, and so on. Here, A[i][j] denotes the value in cell(i,j) of matrix A denotes the cost of writing the letter corresponding to ID j immediately after the letter corresponding to ID i.

Now, you are given a string S consisting of distinct lowercase alphabets and you have to determine the minimum cost to generate any permutation of the given string.

A permutation of a string is the rearrangement of the letters of the string.

NOTE: The cost of writing the first character is zero as no characters are present before the first character.

Input Format:

• The first line contains a single integer N.
• Next N lines contain N space-separated integers denoting matrix A.
• The next line contains a string S.

Output Format:

Print a single integer denoting the minimum cost as explained in the problem.

Constraints:

• 1<=N<=20
• 1<=A[i][j]<=10^9(i!=j)
• A[i][j]=0(i=j)
• 1<=|S|<=N
• S contains letters up to first N letters of lowercase alphabets.
• All characters in S are distinct.

Someone please tell me the approach to solve these problem and also comment what you think about the difficulty level of these questions with respect to Div 2-A,B,C,D,E,F and Problem Rating.