1. 程式人生 > >CF-Codeforces Round #483 (Div. 2) D. XOR-pyramid 區間DP

CF-Codeforces Round #483 (Div. 2) D. XOR-pyramid 區間DP

For an array b of length m we define the function f as


For example, f(1,2,4,8)=f(12,24,48)=f(3,6,12)=f(36,612)=f(5,10)=f(510)=f(15)=15

You are given an array a and a few queries. Each query is represented as two integers l and r. The answer is the maximum value of f on all continuous subsegments of the array a

l,al+1,,ar.

Input

The first line contains a single integer n

(1n5000) — the length of a.The second line contains n integers a1,a2,,an (0ai2301) — the elements of the array.The third line contains a single integer q (1q100000) — the number of queries.

Each of the next qlines contains a query represented as two integers l

, r (1lrn).

Output

Print q lines — the answers for the queries.

ExamplesInput
3
8 4 1
2
2 3
1 2
Output
5
12
Input
6
1 2 4 8 16 32
4
1 6
2 5
3 4
1 2
Output
60
30
12
3
Note

In first sample in both queries the maximum value of the function is reached on the subsegment that is equal to the whole segment.

In second sample, optimal segment for first query are [

3,6], for second query — [2,5], for third — [3,4], for fourth — [1,2].

#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
#define N 5010

int n,q,l,r;
__int64 ans[N][N],dp[N][N],a[N];

int main()
{
    while(~scanf("%d",&n))
    {
        memset(dp,0,sizeof(dp));
        for(int i=1; i<=n; i++)
        {
            scanf("%I64d",&a[i]);
            ans[i][i]=a[i];
            dp[i][i]=a[i];
        }
        for(int l=1; l<n; l++)
        {
            for(int i=1; i+l<=n; i++)
            {
                int j=l+i;
                ans[i][j]=ans[i][j-1]^ans[i+1][j];
                dp[i][j]=max(ans[i][j],max(dp[i+1][j],dp[i][j-1]));
            }
        }
        scanf("%d",&q);
        while(q--)
        {
            scanf("%d%d",&l,&r);
            printf("%I64d\n",dp[l][r]);
        }
    }
    return 0;
}