cf602b approximating a Constant Range

B. Approximating a Constant rangetime limit per test2 secondsMemory limit per testMegabytesInputStandard InputOutputStandard Output

When Xellos is doing a practice course in university, he once had to measure the intensity of a effect that slowly appro ached equilibrium. A good the determine the equilibrium intensity would be choosing a sufficiently large number of consecutive data points That seems as constant as possible and taking their average. Of course, with the usual sizes of data, it's nothing challenging-but why not make a similar programming contest problem While the we ' re at it?

You ' re given a sequence Of  n  data points  a 1, ..., a n .  There aren ' t any big jumps between consecutive data points -for Each 1≤ I < n , it ' s guaranteed that | A i + 1- a i |≤1.

A range [l, R] of data points is said to being almost constant if the difference between the larges T and the smallest value in that range are at most 1. Formally, let m is the maximum and m the minimum value of ai for l ≤ i ≤ r; the range [l, R] is almost constant if m - M ≤1.

Find the length of the longest almost constant range.

Input

The first line of the input contains a single integer n (2≤ n ≤100)-the number of data p Oints.

The second line contains n integers a1, a2, ..., an (1≤ ai ≤100).

Output

Print a single number-the maximum length of a almost constant range of the given sequence.

Examplesinput

5
1 2 3) 3 2

Output

4

Input

11
5 4 5 5 6 7 8 8 8 7 6

Output

5

Note

In the first sample, the longest almost constant range are [2, 5]; its length (the number of data points in it) is 4.

In the second sample, there is three almost constant ranges of length 4: [1, 4], [6, 9] and [7, ten]; the Only almost constant range of the maximum length 5 is [6].

I'm a little surprised. B is the DP, although it is a simple DP

Test instructions is said to give a sequence, to ensure that the adjacent two difference between the value of not more than 1, to find a eldest son string length, required to meet the maximum value of the substring minus the minimum value less than 2

It means that there are only two numbers adjacent to each other in the string.

F[i][1] represents the oldest string that starts with the number of I and contains only a[i] and a[i]+1 two numbers

F[I][2] represents the oldest string that starts with the number of I and contains only a[i] and a[i]-1 two numbers

And then

A[I]==A[I+1] f[i][1]=f[i+1][1] f[i][2]=f[i+1][2]

A[i]==a[i+1]+1 is F[i][1]=1 f[i][2]=f[i+1][1]+1

A[i]==a[i+1]-1 is F[i][2]=1 f[i][1]=f[i+1][2]+1

1#include <cstdio>2#include <iostream>3#include <cstring>4#include <cstdlib>5#include <algorithm>6#include <cmath>7#include <queue>8#include <deque>9#include <Set>Ten#include <map> One#include <ctime> A #defineLL Long Long - #defineINF 0X7FFFFFF - #definePA pair<int,int> the #definePi 3.1415926535897932384626433832795028841971 - using namespacestd; - inline LL read () - { +LL x=0, f=1;CharCh=GetChar (); -      while(ch<'0'|| Ch>'9'){if(ch=='-') f=-1; ch=GetChar ();} +      while(ch>='0'&&ch<='9') {x=x*Ten+ch-'0'; ch=GetChar ();} A     returnx*F; at } -Inlinevoidwrite (LL a) - { -     if(a<0) {printf ("-"); a=-A;} -     if(a>=Ten) Write (ATen); -Putchar (a%Ten+'0'); in } -InlinevoidWriteln (LL a) {write (a);p rintf ("\ n");} to intN,ans; + inta[100010]; - ints1[100010]; the ints2[100010]; * intMain () $ {Panax Notoginsengn=read (); -      for(intI=1; i<=n;i++) a[i]=read (); thes1[n]=s2[n]=ans=1; +      for(inti=n-1; i>=1; i--) A     { the         if(a[i]==a[i+1]) s1[i]=s1[i+1]+1, s2[i]=s2[i+1]+1; +         if(a[i]>a[i+1]) s1[i]=1, s2[i]=s1[i+1]+1; -         if(a[i]<a[i+1]) s2[i]=1, s1[i]=s2[i+1]+1; $ans=Max (Ans,max (s1[i],s2[i)); $     } -printf"%d\n", ans); -}

cf602b

cf602b approximating a Constant Range