MINSTACK  Smallest on the Stack
Every Christmas the good old man can go to every house in the world and leave gifts for the children who have been good throughout the year, but this is only possible because of his magic gift bag. It would be impossible for Santa to carry all the presents in his bag, the volume and weight of them all makes this obviously unfeasible. What actually happens is that your bag is a kind of magical portal to your gift factory at the North Pole. Where the presents are stacked by their elves and Noel always takes the gift from the top of that pile when he accesses his magical bag.
Gifts have a numerical measure of the degree of fun they can provide children, and Santa is always concerned with the least fun gift he will deliver throughout the night because he does not want any child to feel bad about it. you receive. However, this can not be done in advance because throughout the night as the good old man takes gifts from the pile to deliver, others are still being made and placed on the pile. So the most he can know is the value of the least fun present on the stack up to that point.
Your task is, given the sequence of operations done on the stack of gifts, answer Santa's queries about the value of the least entertaining gift on the stack thus far.
Input
The first line of the input contains an integer N (1 ≤ N ≤ 10^{6}) corresponding to the number of operations performed on the present stack. The operations can be of three types: "PUSH V" where V (1 ≤ V ≤ 10^{9}) is an integer representing the degree of fun of the present being placed on the stack; "POP" which represents that Santa Claus is taking a gift from the cell to deliver and "MIN" representing a Noel query to know the smallest gift value in the stack.
Output
The output consists of a line containing an integer with the smallest present value in the stack for queries of type "MIN" or "EMPTY" for "MIN" and "POP" operations when the stack is empty.
Example
Input: 11
PUSH 5
PUSH 7
PUSH 3
PUSH 8
PUSH 10
MIN
POP
POP
MIN
POP
MIN Output:3
3
5
Example
Input: 9
PUSH 100
PUSH 50
MIN
PUSH 45
MIN
POP
MIN
POP
MIN Output:50
45
50
100
hide comments
nemish1999:
20200625 07:15:59
Hi, it's also giving me time limit problem in c++, even for o(1) solution. what's a problem wih this problem.even o(1) is not enough for him. then how can i predict the next move? now do i have to guess!!!!!! 

tarun_28:
20200601 23:36:09
Implement multiset!! 

abhishekv18:
20191224 19:12:24
don't forget to print EMPTY in case of empty stack :) 

kh_q:
20191110 05:58:00
Where I can find solution with c++?? 

[Lakshman]:
20191109 04:35:24
@shriman_chetan I got AC with Java without fast IO. 

Simes:
20191108 14:39:47
@shriman_chetan: Yes, but that's 1.7 seconds in total across the 10 or so test cases, and each test case is allowed between 1 and 1.2 seconds.


shriman_chetan:
20191108 12:48:24
@Simes Look at the date of those java solution and also the time limit in which they executed. The fastest one was 1.7 seconds while the original limit of problem has been reduced to 1.2 second at most. It clearly means that the time has been reduced for original problem later. And since then, no one has been able to do it in Java. :( :( :( I also did this problem with my old ID, 1 year ago. Same code fails now. 

Simes:
20191108 11:16:18
There are Java solutions https://www.spoj.com/ranks/MINSTACK/lang=JAVA 

shriman_chetan:
20191107 20:11:57
Seems like this is also an AntiJava problem.

Added by:  Francisco Elio Parente Arcos Filho [UEA] 
Date:  20181224 
Time limit:  1s1.200s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All 