<p>You are given an array <code>nums</code> consisting of non-negative integers. You are also given a <code>queries</code> array, where <code>queries[i] = [x<sub>i</sub>, m<sub>i</sub>]</code>.</p>

<p>The answer to the <code>i<sup>th</sup></code> query is the maximum bitwise <code>XOR</code> value of <code>x<sub>i</sub></code> and any element of <code>nums</code> that does not exceed <code>m<sub>i</sub></code>. In other words, the answer is <code>max(nums[j] XOR x<sub>i</sub>)</code> for all <code>j</code> such that <code>nums[j] &lt;= m<sub>i</sub></code>. If all elements in <code>nums</code> are larger than <code>m<sub>i</sub></code>, then the answer is <code>-1</code>.</p>

<p>Return <em>an integer array </em><code>answer</code><em> where </em><code>answer.length == queries.length</code><em> and </em><code>answer[i]</code><em> is the answer to the </em><code>i<sup>th</sup></code><em> query.</em></p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> nums = [0,1,2,3,4], queries = [[3,1],[1,3],[5,6]]
<strong>Output:</strong> [3,3,7]
<strong>Explanation:</strong>
1) 0 and 1 are the only two integers not greater than 1. 0 XOR 3 = 3 and 1 XOR 3 = 2. The larger of the two is 3.
2) 1 XOR 2 = 3.
3) 5 XOR 2 = 7.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums = [5,2,4,6,6,3], queries = [[12,4],[8,1],[6,3]]
<strong>Output:</strong> [15,-1,5]
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= nums.length, queries.length &lt;= 10<sup>5</sup></code></li>
	<li><code>queries[i].length == 2</code></li>
	<li><code>0 &lt;= nums[j], x<sub>i</sub>, m<sub>i</sub> &lt;= 10<sup>9</sup></code></li>
</ul>

class Node{
    public:
    Node* links[2];
    bool flag =false;

    bool contains(int x){
        return links[x]!=NULL;
    }
    void put(int x,Node* node){
        links[x]=node;
    }
    Node*get(int x){
        return links[x];
    }
    void set(){
        flag=true;
    }
    bool isend(){
        return flag;
    }
};
class Trie {
    Node* root;
public:
    Trie() {
        root=new Node();
    }
    
    void insert(int num) {
        Node* node=root;
        for(int i=31;i>=0;i--){
            int bit=(num>>i)&1;
            if(!node->contains(bit)){
                node->put(bit,new Node());
            }
            node=node->get(bit);
        }
        node->set();
    }
    int getmax(int num){
        Node* node=root;
        int ans=0;
        for(int i=31;i>=0;i--){
            int bit=(num>>i)&1;
            if(node->contains(1-bit)){
                ans=ans| (1<<i);
                node=node->get(1-bit);
            }
            else{
                node=node->get(bit);
            }
            
        }
        return ans;
    }
};
    static bool comp(vector<int>&a,vector<int>&b){
        return a[1]<b[1];
    }
class Solution {
public:
    vector<int> maximizeXor(vector<int>& nums, vector<vector<int>>& queries) {
        int n=queries.size();
        sort(nums.begin(),nums.end());
        vector<vector<int>>temp;
        vector<int>ans(n,0);
        for(int i=0;i<n;i++){
            vector<int>store;
            store.push_back(queries[i][0]);
            store.push_back(queries[i][1]);
            store.push_back(i);

            temp.push_back(store);
        }
        sort(temp.begin(),temp.end(),comp);
        Trie trie;
        int m=nums.size();
        int i=0;
        for(auto it: temp){
            int num=it[0];
            int limit=it[1];
            int idx=it[2];
            while(i<m&&nums[i]<=limit){
                trie.insert(nums[i]);
                i++;
            }
            if (i == 0) { // No valid number inserted before the limit
                ans[idx] = -1;
            } else {
                int maxi = trie.getmax(num);
                ans[idx] = maxi;
            }
        }
        return ans;
        
    }
};
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