Lido Learning Software Developer Intern Interview Questions, Process, and Tips

Round duration - 70 Minutes
Round difficulty - Medium

Timing was 9:15AM. Platform was not very good. Questions were not well explained.

Q1. 
Merge Overlapping Intervals Problem Statement
Given a specified number of intervals, where each interval is represented by two integers denoting its boundaries, the task is to merge all overlapping interv...read more
Ans. Brute Force
1. We are given the function MERGEINTERVALS(), which takes a 2D vector representing the vector of intervals and returns another 2D vector which is the vector of merged intervals.
2. We create another function ISOVERLAP() to check if the current interval overlaps with the other interval.
3. Now we create an empty 2D vector “RES” to store finally merged intervals and another boolean vector “VIS” to mark if the current in...read more
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Q2. 
Rat in a Maze Problem Statement
You need to determine all possible paths for a rat starting at position (0, 0) in a square maze to reach its destination at (N-1, N-1). The maze is represented as an N*N ma...read more
Ans. Bactracking
Approach: We can start the traversal of the paths from the rat’s starting position, i.e. (0,0) keeping track of the visited cells during the traversal. We will recursively go through all the paths possible until the last index of the grid (destination) is reached, and add the path information using which the rat successfully reached the end.
 
Algorithm is as follows:
 
1. Take the starting position of th...read more
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Q3. 
Problem: Permutations of a String
Given a string STR consisting of lowercase English letters, your task is to return all permutations of the given string in lexicographically increasing order.
Explanatio...read more
Ans. Backtracking
The idea is to fix a character at a position and then find the permutations for rest of the characters.
Make a list ‘ans’ which will contain the permutations of the given string.
 
Algorithm:
Let’s define a function generatePermutaionsHelper(Str, l, r). This function generates the permutations of the substring which starts from index  ‘l’ and ends at index  ‘r’.
• Call the function: generatePermutai...read more
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Round duration - 70 minutes
Round difficulty - Medium

Timing was 9:15AM. Platform was not very good. Questions were not well explained.

Q1. 
Merge Overlapping Intervals Problem Statement
Given a specified number of intervals, where each interval is represented by two integers denoting its boundaries, the task is to merge all overlapping interv...read more
Add your answer
Q2. 
Rat in a Maze Problem Statement
You need to determine all possible paths for a rat starting at position (0, 0) in a square maze to reach its destination at (N-1, N-1). The maze is represented as an N*N ma...read more
Add your answer

Round duration - 120 minutes
Round difficulty - Easy

Q1. 
Find All Pairs Adding Up to Target
Given an array of integers ARR of length N and an integer Target, your task is to return all pairs of elements such that they add up to the Target.
Input:
The first line ...read more
Ans. Hashing Solution
• We can store the frequency of every element in the array in a hashmap.
• We will loop over every index i, and check the frequency of (Target - ARR[i]) is the hashmap:
  • If (Target - ARR[i]) is equal to ARR[i], we will check if frequency of ARR[i] . If it is greater than 1 then we will decrease the frequency of ARR[i] by 2 and add a pair (ARR[i] , ARR[i]) to our answer.
  • Else, if the frequency of ARR[i] and Targ...read more
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