Apart from this practice this question(it was hardest in my set others r too simple):
-there is array containing arriving time in shorted array
-there is a progression room where 1 element will stay for 5min and then it will leave
-at a time only 1 element can stay in room
-u have 10 waiting room where element can stay for as long as it want, but u have to make sure each element of waiting room will go to progression room when it's turn comes (order is according to arrival time)
-if a new element comes and there is no place in waiting time u have to skip it
-u have to return the last time when ur progression room was active (that is the last element's 5min time)
-array is int type representing time in seconds
-constrains was easy ig array size 100, and max arriving time was 1000 (or 1000 ans 100 i don't remember)