FREQUENT - Frequent values


You are given a sequence of n integers a1 , a2 , ... , an in non-decreasing order. In addition to that, you are given several queries consisting of indices i and j (1 ≤ i ≤ j ≤ n). For each query, determine the most frequent value among the integers ai , ... , aj.

Input Specification

The input consists of several test cases. Each test case starts with a line containing two integers n and q (1 ≤ n, q ≤ 100000). The next line contains n integers a1 , ... , an (-100000 ≤ ai ≤ 100000, for each i ∈ {1, ..., n}) separated by spaces. You can assume that for each i ∈ {1, ..., n-1}: ai ≤ ai+1. The following q lines contain one query each, consisting of two integers i and j (1 ≤ i ≤ j ≤ n), which indicate the boundary indices for the query.

The last test case is followed by a line containing a single 0.

Output Specification

For each query, print one line with one integer: The number of occurrences of the most frequent value within the given range.

Sample Input

10 3
-1 -1 1 1 1 1 3 10 10 10
2 3
1 10
5 10
0

Sample Output

1
4
3

A naive algorithm may not run in time!

hide comments
Shrish Lal Bhatnagar: 2016-07-25 16:24:03

AC in O(n) preprocessing and O( log (n) ) for each query

kiwi1995: 2016-07-06 06:39:24

memory problem :(
RUN time error..:'(
now TLE..:O

Last edit: 2016-07-06 07:06:46
karthik1997: 2016-06-02 19:04:31

Well You can also use MO's algorithm with either O(N*sqrt(N) ) or O(N*sqrt(N)*log(N)) algorithm :p

minhthai: 2016-01-14 10:34:44

tle in java :(

anshal dwivedi: 2015-12-25 06:44:56

Yo! AC in one go....! XD

infernodragon: 2015-11-25 21:10:26

there are quite a few cases which should be taken care of while merging, this is the most important step in this problem

Ayush Kedia: 2015-05-24 13:46:17

Nope!! @anant_dadu

anant_dadu: 2015-05-24 08:09:33

Last edit: 2015-05-25 12:53:46
Sunil: 2015-04-28 21:48:55

bridges, mse06h , niceday are all very similar problems

GAURAV CHANDEL: 2015-04-20 12:55:56

Very good segment tree problem....


Added by:Adrian Kuegel
Date:2007-07-06
Time limit:1s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ERL JS-RHINO NODEJS PERL6 VB.NET
Resource:University of Ulm Local Contest 2007