Cousins in Binary Tree

Cousins in Binary Tree

In a binary tree, the root node is at depth 0, and children of each depth k node are at depth k+1.

Two nodes of a binary tree are cousins if they have the same depth, but have different parents.

We are given the root of a binary tree with unique values, and the values x and y of two different nodes in the tree.

Return true if and only if the nodes corresponding to the values x and y are cousins.

 

Example 1:

Input: root = [1,2,3,4], x = 4, y = 3
Output: false

Example 2:

Input: root = [1,2,3,null,4,null,5], x = 5, y = 4
Output: true

Example 3:

Input: root = [1,2,3,null,4], x = 2, y = 3
Output: false

 

Constraints:

• The number of nodes in the tree will be between 2 and 100.
• Each node has a unique integer value from 1 to 100.

 

 

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    TreeNode* ht(TreeNode* root,int x,int &cnt)
    {
        if(root==NULL)return 0;
        queue<TreeNode*> q;
        int l=0;
        q.push(root);
        TreeNode* p1=NULL;
        while(!q.empty())
        {
            int s=q.size();
            int f=1;
            while(s--)
            {
                if(f)
                {
                    ++cnt,f=0;
                }
                auto  k=q.front();
                q.pop();  
                if(k->left){
               if(k->left->val==x)
                {
                    p1=k;
                    l=1;
                    break;
                }
                    q.push(k->left);
                }
                if(k->right){
              if(k->right->val==x)
                {
                    p1=k;
                     l=1;
                     break;
                 }
                 q.push(k->right);}
            }
            if(l)break;
        }    
        return p1;
    }

    bool isCousins(TreeNode* root, int x, int y) {
        int h1=0,h2=0;
       TreeNode* p1=ht(root,x,h1);
        // cout<<h1<<" "<<p1->val<<" -";
        TreeNode* p2=ht(root,y,h2);
        // cout<<h2<<" "<<p2->val;
        if(h1==h2&&p1!=p2)
            return true;
        else
            return false;
    }
};