# Category: Software Development Engineer in Test

## Convert Prefix to Postfix Expression

Objective: Given a Prefix expression, write an algorithm to convert it into Postfix expression. Example: Input: Prefix expression:  + A B  Output: Postfix expression: A B + Input: Prefix expression:  *-A/BC-/AKL Output: Postfix expression:...

## Convert Roman Number to Integer

Objective: Given a Roman number, write a program to convert it to Integer. Roman Number –   Letters used in Roman numerals and the corresponding numerical values are given in the table below. Rules: ...

## Convert Postfix to Prefix Expression

Objective: Given a Postfix expression, write an algorithm to convert it into prefix expression. Example: Input: Postfix expression:  A B +  Output: Prefix expression- + A B Input: Postfix expression:  ABC/-AK/L-* Output: Infix expression:...

## String to Integer (AtoI – ASCII to Integer) – Recursive Solution

Objective: Write a recursive function to implement atoi, which converts string to an integer. Rules for converting string to an integer. If the string is null or empty, Integer will be 0. The first...

## Grouping of Anagrams

Objective: Given an array of strings, write an algorithm to group the anagrams. Example: Input: [rat, art, cat, act, dog, god, tar, pat] Output: [rat, art, tar] [cat, act] [pat] [dog, god] Approach:  If...

## Print Processes and its messages from a given log file

Problem Statement:  There is an application that has several processes running in parallel and each process prints the logs in a single log file. Log message contains the process name, timestamp, message type (WARN,...

## Longest contiguous character in a given String – O(N) Solution

Objective: Given an input string, write an algorithm to find the longest contiguous character or in other words, find a maximum consecutive character in the string. Example: Input: “aaabbccccddbbaaa” Output: c, count = 4...

## Convert Postfix to Infix Expression

Objective: Given a Postfix expression, write an algorithm to convert it into Infix expression. Example: Input: Postfix expression:  A B +  Output: Infix expression- (A + B) Input: Postfix expression:  ABC/-AK/L-* Output: Infix expression:...

## String to Integer (AtoI – ASCII to Integer)

Objective: Implement atoi, which converts string to an integer. Rules for converting string to an integer. If the string is null or empty, Integer will be 0. The first character of string may represent...

## Longest substring with at most two unique characters

Objective: Given a string, write an algorithm to find the longest substring with at most two characters. Example: Input: aabbccddc Output: ccddc, length: 5 Input: aabacbeeeebeaabb Output: beeeebe, length 7 Input: aaaaaa Output: Only...

## Monotone Increasing Digits

Objective: Given a number N, find the largest number which is less than equal to N and has monotone increasing digits. Monotone Increasing Digits – If all the pairs (x, y) of adjacent digits...

## Convert Prefix to Infix Expression

Objective: Given a Prefix expression, write an algorithm to convert it into Infix expression. Example: Input: Prefix expression: + A B Output: Infix expression- (A + B) Input: Prefix expression: *-A/BC-/AKL Output: Infix expression:...

## Convert Infix to Prefix Expression

Objective: Given an Infix expression, write an algorithm to convert it into Prefix expression. Example: Input: Infix expression – A + B Output: Prefix expression- +AB Input: Infix expression – A+B*(C^D-E) Output: Prefix expression-...

## Find duplicates Characters in the given String

Objective: Given a string, write an algorithm to find all the duplicate characters in the string and print its count. Example: Input String: tutorial horizon Output: Duplicate Characters: r – 2 t – 2...

## Max Flow Problem – Ford-Fulkerson Algorithm

Objective: Given a directed graph that represents a flow network involving source(S) vertex and Sink (T) vertex.  Each edge in the graph has an individual capacity which is the maximum flow that edge allows....