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
yash_18: 2016-06-04 08:53:02

used java TLE!!
used c++ accepted.

aloochaat1998: 2016-05-22 08:20:30

Anybody who doesn't have a approach,refer this:

minhthai: 2016-01-23 15:36:23

nlogn and tle, what to do :((

senshiya: 2016-01-23 11:13:27

plz provide some test cases i m getting wrong ans....

waelalgaml: 2015-12-03 21:44:14

getting tle in test case 8 -_-

vedang: 2015-11-30 14:16:47

My 150th :')
Used a nice little trick after several TLEs.

harry30: 2015-11-29 09:19:03

is there a clue how to produce output 36 on second sample test case ?

jkelava6: 2015-10-23 21:02:20

I think that time limit is too strict for Python, if you are using the solution that is meant to be used on this problem!
I mean, I have accepted it on C++... Now getting TLE with Python 3, using the SAME idea.

maverick_10: 2015-09-16 22:34:45

It's a very good and basic problem for implementing binary search I think .

monkz: 2015-09-03 20:00:24

does nlogn solution work??
im getting tle for n logn

Last edit: 2015-09-03 20:42:13

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