CodeForces-485D Maximum Value(暴力)

D. 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 by aj), 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.

Examples

input

3
3 4 5

output

2

题解:排序后,枚举每个数a[i],然后再枚举a[i]的倍数k*a[i],找到k*a[i]~(k+1)*a[i]中模上a[i]的最大的数,那个数一定是小于(k+1)*a[i]的最大数,然后取模后与答案比较,取最大值

#include<cstdio>
#include<queue>
#include<string.h>
#include<algorithm>
#include<stack>
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define FIN freopen("in.txt","r",stdin)
using namespace std;
typedef long long LL;
typedef pair<int,int> PII;
const int maxn = 2e5 + 5;
int a[maxn];
int main(){
    int n;
  //  FIN;
    scanf("%d",&n);
    for(int i=0;i<n;i++) scanf("%d",&a[i]);
    sort(a,a+n);
    int nn=1;
    for(int i=1;i<n;i++) if(a[i]>a[i-1]) a[nn++]=a[i];
    n=nn;
    int ans=0;
    for(int i=0;i<n-1;i++){
        for(int j=a[i];j<a[n-1];j+=a[i]){
            int pos=lower_bound(a+i+1,a+n,j+a[i])-a;
            ans=max(ans,a[pos-1]%a[i]);
        }
    }
    printf("%d\n",ans);
    return 0;
}