Logics

Question 1

Ugly Number

Answer 1

Take minimum from 2* 3* 5*. Order is important. Maintain three indexes or Set

Question 2

Merge Intervals

Answer 2

Take List of int[]
if(last[1] < next[0]) – just add it
else merge it – update last end to max

Question 3

Insert Intervals

Answer 3

add all intervals less than new one - compare with start
add new interval and merge if need
do the merge interval logic from here