hackerrank and other mind teaser problems

Almost Sorted

Alternating Characters

Anagrams Lists

Angry Children

Find Digits

First Unique Integer

Highest Spike

Insertion Sort

Insertion Sort Complexity

Insertion Sort Invariant

Is Fibonacci

Longest Containing String

Love Letter Mystery

Max Xor

Minimal Common

Minimum Absolute Difference

Non Ascending Subsequence

Palindrome Index

Pangrams

Permutations

Remove Duplicates

Sub Array Sum

Team Formation

Test Booking (Array Subtraction)

Utopia Tree

Words to Number