DSA/C++/LeetCode/0421.cpp at main · spycedcoffee/DSA · GitHub

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class Trie{
public:
    Trie* left;
    Trie* right;
};

Trie* insertNode(Trie* head, int val){

    Trie* curr = head;

    for(int i = 31; i >= 0; i--){

        int bit = (val >> i) & 1;

        if(bit == 0){
            if(!curr -> left)
                curr -> left = new Trie();

            curr = curr -> left;
        }
        else{
            if(!curr -> right)
                curr -> right = new Trie();

            curr = curr -> right;
        }
    }

    return head;
}

class Solution {
public:
    int calXor(Trie* head, vector<int>& nums){

        int maxVal = INT_MIN;

        for(int i = 0; i < nums.size(); i++){

            int val = nums[i];
            int temp = 0;

            Trie* curr = head;

            for(int j = 31; j >= 0; j--){

                int bit = (val >> j) & 1;;

                if(bit == 0){

                    if(curr -> right){
                        temp += pow(2, j);
                        curr = curr -> right;
                    }

                    else
                        curr = curr -> left;
                }

                else{

                    if(curr -> left){
                        temp += pow(2, j);
                        curr = curr -> left;
                    }

                    else
                        curr = curr -> right;
                }
            }
            maxVal = max(maxVal, temp);
        }

        return maxVal;
    }

    int findMaximumXOR(vector<int>& nums) {

        Trie* head = new Trie();

        for(int i = 0; i < nums.size(); i++)
            head = insertNode(head, nums[i]);

        return calXor(head, nums);
    }
};