[TOJ 5065] the longest continuous subsequence and the longest toj5065

[TOJ 5065] the longest continuous subsequence and the longest toj5065

Description

Given a series of non-negative integers, find the longest continuous subsequence so that it is a multiple of 7.

Input

The first positive integer is N (1 <=n <= 50000), followed by N rows, each row has a non-negative integer, and All integers are not greater than 10 ^ 6.

Output

If a continuous subsequence exists and the subsequence is a multiple of 7, the length of the subsequence is output. If the subsequence does not exist, 0 is output.

Sample input

7
3
5
1
6
2
14
10

Sample output

5

#include<iostream> #include<cstring>#include<algorithm>using namespace std;int main(){    int n,i,j,a[50001],right[9],left[9],maxx=0,len;    cin>>n;    memset(right,-1,sizeof(right));    memset(left,-1,sizeof(left));    a[0]=0;    left[0]=0;    for(i=1;i<n;i++)    {        scanf("%d",&a[i]);        a[i]=(a[i-1]+a[i])%7;        if(left[a[i]]==-1)        left[a[i]]=i;    }    for(i=n-1;i>=0;i--)    {        if(right[a[i]]==-1)            right[a[i]]=i;    }    for(i=0;i<=8;i++)    {        for(j=0;j<=8;j++)        {            if(right[i]>=0&&left[j]>=0&&i==j)            {                len=right[i]-left[j];                maxx=max(len,maxx);            }        }    }    cout<<maxx<<endl;    return 0;}