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
cat_got_bored: 2017-01-01 19:21:47

Testcases to check. http://spojtoolkit.com/history/FREQUENT

papan_97: 2016-12-15 19:42:06

my 100th ... :) :) :) and AC in one go with segment tree

king: 2016-12-13 08:57:32

At last AC, A must do question of segment tree

Abhishek Kainth: 2016-12-12 22:50:16

O(N*log(N)) precomputation using Sparse Table
O(1) per query :D

elliot1: 2016-11-02 00:09:30

what to do in case of a tie !!

santamaria: 2016-10-16 06:23:59

o.O OMG !!, this shit is solved ... :D

shubham: 2016-09-13 16:04:51

AC in one go... concept similar to http://www.spoj.com/problems/GSS1/
using prefix sum and suffix sum..

onlyappleapp: 2016-08-29 14:19:02

Attention : The input consists of several test cases ! :-)

hashem sllat: 2016-08-19 11:00:32

is there any approach to solve this problem in O(n*log(n) ) when array is not sorted ?

kumar gaurav: 2016-08-17 21:29:59

getting TLE, even if O(n) for preprocessing and O(log n) for each queries.


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