SDE - 1

You have been given an array/list of integers 'ARR' of size 'N'. Your task is to find two things-

1. The number of elements that are occurring an Odd number of times.

2. The number of elements that are occurring Even a number of times.

For Example:

ARR = [2, 1, 2, 1, 5, 5, 2]    
Output: 1 2 

2 occurs three(odd) times.
1 occurs two(even) times.
5 occurs two(even) times.

So, the total 1 element is occurring an odd number of times and 2 elements are occurring an even number of times.

SQL query to find second highest salary

You are given a number ‘N’ as a string in base ‘B’. Your task is to convert ‘N’ in base 10. If it’s impossible to convert ‘N’ into base 10, then you need to print -1.

Note :

1. ‘N’ contains only digits ‘0’ to ‘9’ and English letters ‘A’ to ‘F’.
2. Decimal equivalent of 0 is 0, 1 is 1, . . .9 is 9, A is 10, B is 11, . . . F is 15.

You have been given a number of stairs. Initially, you are at the 0th stair, and you need to reach the Nth stair.

Each time, you can climb either one step or two steps.

You are supposed to return the number of distinct ways you can climb from the 0th step to the Nth step.

Note:

Note: Since the number of ways can be very large, return the answer modulo 1000000007.

Example :

N=3

We can climb one step at a time i.e. {(0, 1) ,(1, 2),(2,3)} or we can climb the first two-step and then one step i.e. {(0,2),(1, 3)} or we can climb first one step and then two step i.e. {(0,1), (1,3)}.

You are given 4 arrays 'ARR1’, 'ARR2’, 'ARR3’, 'ARR4’, each consists of ‘N’ numbers. Your task is to return the number of tuples (i, j, k, l) satisfying the following conditions:

0 <= i,j,k,l < ‘N’
ARR1[i] + ARR2[j] + ARR3[k] + ARR4[l] = 0.

Design a compiler with your knowledge of engineering till now.