B. Maximum Value
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output
You are given a sequence a consisting of n integers. Find the maximum possible value of (integer remainder of ai divided byaj), where 1?≤?i,?j?≤?n and ai?≥?aj.
Input
The first line contains integer n ? the length of the sequence (1?≤?n?≤?2·105).
The second line contains n space-separated integers ai (1?≤?ai?≤?106).
Output
Print the answer to the problem.
Sample test(s)
input
33 4 5
output
<strong>找a[i]<a></a></strong>
<strong>由于ai</strong>
<strong>至于找最大模后的值，取a[i]==i也就是这个点存在，取模后的最大值肯定i+1+k*i,这样每次增加i查询，</strong>
<strong>查到离最大值最近的值。</strong>
<strong>代码：</strong>
<strong></strong><pre name="code" class="n">#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;const int maxn=2000000+100;int a[maxn];int main(){ int n; scanf("%d",&n); int x; for(int i=0;i<n scanf a for i="0;i<maxn;i++)" if int ans="0;" j="i+i-1;j<maxn;j=j+i)">ans&&a[j]>i) ans=a[j]%i; } } } printf("%d\n",ans); return 0;}</n></algorithm></cstring></cstdio></iostream>
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