Codeforces 984 D - XOR-pyramid

#include<bits/stdc++.h>
using namespace std;
#define LL long long 
#define pb push_back
#define mem(a, b) memset(a, b, sizeof(a))

const int N = 5e3 + 5;
int dp[N][N], a[N];
int main() {
    int n, q, l, r;
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
    for (int i = n; i >= 1; i--) {
        dp[i][i] = a[i];
        for (int j = i+1; j <= n; j++) {
            dp[i][j] = dp[i][j-1] ^ dp[i+1][j];
        }
    }
    for (int i = n; i >= 1; i--) {
        for (int j = i+1; j <= n; j++) {
            dp[i][j] = max(dp[i][j], max(dp[i][j-1], dp[i+1][j]));
        }
    }
    scanf("%d", &q);
    while(q--) {
        scanf("%d %d", &l, &r);
        printf("%d\n", dp[l][r]);
    }
    return 0;
}