EKO - Eko

Lumberjack Mirko needs to chop down M metres of wood. It is an easy job for him since he has a nifty new woodcutting machine that can take down forests like wildfire. However, Mirko is only allowed to cut a single row of trees.

Mirko‟s machine works as follows: Mirko sets a height parameter H (in metres), and the machine raises a giant sawblade to that height and cuts off all tree parts higher than H (of course, trees not higher than H meters remain intact). Mirko then takes the parts that were cut off. For example, if the tree row contains trees with heights of 20, 15, 10, and 17 metres, and Mirko raises his sawblade to 15 metres, the remaining tree heights after cutting will be 15, 15, 10, and 15 metres, respectively, while Mirko will take 5 metres off the first tree and 2 metres off the fourth tree (7 metres of wood in total).

Mirko is ecologically minded, so he doesn‟t want to cut off more wood than necessary. That‟s why he wants to set his sawblade as high as possible. Help Mirko find the maximum integer height of the sawblade that still allows him to cut off at least M metres of wood.


The first line of input contains two space-separated positive integers, N (the number of trees, 1 ≤ N ≤ 1 000 000) and M (Mirko‟s required wood amount, 1 ≤ M ≤ 2 000 000 000).

The second line of input contains N space-separated positive integers less than 1 000 000 000, the heights of each tree (in metres). The sum of all heights will exceed M, thus Mirko will always be able to obtain the required amount of wood.


The first and only line of output must contain the required height setting.


4 7
20 15 10 17

5 20
4 42 40 26 46


hide comments
roshansalian: 2020-11-07 17:06:52

Failing case 9 can mean a very silly binary search mistake.

aayush_kansara: 2020-10-17 06:40:15

one of the best problem for binary search

kakashi_kd: 2020-10-12 16:18:09

Those getting wrong answer . check if you are taking no of test cases as input. as in this question , we donot take the no of test cases as input

milind30: 2020-09-19 07:37:23

Nice and easy one for Binary Search. Similar to Book Allocation Problem.

bhavneet2000: 2020-08-24 20:55:01

Nice and simple :)

sk11__: 2020-07-31 21:51:05

Getting wrong answer at Test case 9. tried using long long int as well

wille_25: 2020-07-29 13:03:06

AC in one go ...bruh!!!!!...just use the concept of binary search that's it ;

danny_132: 2020-07-26 10:52:38

Really good problem on Binary search . This basically involves the concept of binary search on answer where we decide which side will give better answer(left or right if some condition satisfies) after finding the mid. Watch video on Binary search by ERRICHTO he has explained the concept really well using the largest >=x problem in his video.

sukhseerat_123: 2020-07-17 10:08:23

Why is it giving TLE in python code?? My logic is absolutely correct with O(nlog(n)) time complexity ???

mob_physcho100: 2020-07-04 09:59:34

AC in one go

Added by:ghorvat
Time limit:1s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Resource:COCI 2011/2012