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
Dharak Kharod: 2015-07-13 21:41:06

fell in love with binary search all over again! :D

harshit sharma: 2015-06-17 06:58:30

150 th... :)
still binary search amaze m...

i_am_looser: 2015-05-26 16:03:54

Binary search yeeeeeeeeeeeeeeeeeeeeh..... ; )

johntyro: 2015-05-03 11:22:39

Remember to use long long

Kshitij Agarwal: 2015-04-11 07:34:02

Any tricky test cases?
getting wrong answer in test case 8

Last edit: 2015-04-11 07:34:55
Hardik Dosi: 2014-12-23 11:31:54

Really nice question ;-)

Mitch Schwartz: 2012-08-16 06:10:34

For some time now, the way SPOJ judge works is to run user's submitted program against ALL input files, and only afterward report the status according to success or the first failure. Many recent comments for various problems have assumed that SPOJ judge halts on first failure, leading to an unfounded belief that the last input file is especially tricky.

Last edit: 2012-08-16 06:11:10

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