3287. 求出数组中最大序列值

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题目链接：3287. 求出数组中最大序列值

代码如下：

//参考链接：https://leetcode.cn/problems/find-the-maximum-sequence-value-of-array/solutions/3037275/qiu-chu-shu-zu-zhong-zui-da-xu-lie-zhi-b-bhnk
class Solution {
public:int maxValue(vector<int>& nums, int k) {auto findORs = [&](const vector<int>& nums, int k)->vector<unordered_set<int>> {vector<unordered_set<int>> dp;vector<unordered_set<int>> prev(k + 1);prev[0].insert(0);for (int i = 0;i < nums.size();i++) {for (int j = min(k - 1, i + 1);j >= 0;--j) {for (int x : prev[j]) {prev[j + 1].insert(x | nums[i]);}}dp.push_back(prev[k]);}return dp;};vector<unordered_set<int>> A = findORs(nums, k);vector<unordered_set<int>> B = findORs(vector<int>(nums.rbegin(), nums.rend()), k);int mx = 0;for (int i = k - 1;i < nums.size() - k;i++) {for (int a : A[i]) {for (int b : B[nums.size() - i - 2]) {mx = max(mx, a ^ b);}}}return mx;}
};