3277. Maximum XOR Score Subarray Queries

You are given an array nums of n integers, and a 2D integer array queries of size q, where queries[i] = [li, ri].

For each query, you must find the maximum XOR score of any subarray of nums[li..ri].

The XOR score of an array a is found by repeatedly applying the following operations on a so that only one element remains, that is the score:

• Simultaneously replace a[i] with a[i] XOR a[i + 1] for all indices i except the last one.
• Remove the last element of a.

Return an array answer of size q where answer[i] is the answer to query i.

int dp[2020][2020], dpp[2020][2020];
class Solution {
    int helper(vector<int>& A, int l, int r) {
        if(dp[l][r] != -1) return dp[l][r];
        if(l == r) return dp[l][r] = dpp[l][r] = A[l];
        int& res = dp[l][r] = max({helper(A,l+1,r), helper(A,l,r-1)});
        dpp[l][r] = dpp[l+1][r] ^ dpp[l][r-1];
        res = max(res, dpp[l][r]);
        return res;
    }
public:
    vector<int> maximumSubarrayXor(vector<int>& nums, vector<vector<int>>& queries) {
        memset(dp,-1,sizeof dp);
        memset(dpp,-1,sizeof dpp);
        vector<int> res;
        for(auto& q : queries) {
            res.push_back(helper(nums,q[0],q[1]));
        }
        return res;
    }
};