@cassidoo's Interview question of the week for June 6, 2021

lonelyNumber.sh

#!/usr/bin/env bash
set -eu -o pipefail

# lonelyNumber.sh
# @cassidoo 2021-06-06
# Given three numbers, return their product. But, if one of the numbers is the same as
# another, it does not count: If two numbers are similar, return the lonely number. If all
# numbers are same, return 1. 

if [ $# -ne 3 ] || ! ([[ $1 =~ ^[0-9]+$ ]] && [[ $2 =~ ^[0-9]+$ ]] && [[ $3 =~ ^[0-9]+$ ]]); then
  echo "$(basename $0): enter three postive integers"
  exit 1
fi

PRODUCT=$(($1*$2*$3))
if [ $(($1**3)) -eq $PRODUCT ]; then
  echo 1
elif [ $1 -eq $2 ]; then
  echo $3
elif [ $1 -eq $3 ]; then
  echo $2
elif [ $2 -eq $3 ]; then
  echo $1
else
  echo $PRODUCT
fi