Coding Problems

Convert temperature from Fahrenheit to Celsius.

Count the number of vowels in a given string.

Find the length of a string without using built-in functions

Given a string, print it in reverse order.

Calculate sum of all digits in a number

Count the number of digits in a number

Count how many even numbers are in an array

Swap the values of two variables and print them.

Calculate simple interest given principal, rate, and time.

Count the number of connected components in an undirected graph

Determine if a graph is a valid tree (no cycles, fully connected)

Determine the order of letters in an alien language

Find cells where water can flow to both Pacific and Atlantic oceans

Find the length of shortest transformation sequence from beginWord to endWord

Write a program to solve a Sudoku puzzle

Find all unique combinations where candidate numbers sum to target

Return all possible permutations of a collection of distinct integers

Find the length of the longest consecutive elements sequence

Find the duplicate number in an array of integers

Create a deep copy of a linked list with random pointers