Q1 ) sum of all Happy Number for the given range.

input: start=19, end=22
output: 19

Explanation: no. from 19 to 22
19 ( Happy No.)
20 (Not Happy No.)
21 (Not Happy No.)
22 (Not Happy No.)

Hence add 19 to result.

i tried same approch loop detection, but still got TLE ,
also added chache at isHappyNum() and getSqrSum() to speedup , but still TLE

Q2) https://leetcode.com/discuss/interview-question/1194238/paypal-max-tasks-that-can-be-completed-in-given-budget