Leetcode same Tree

1. Topics

Given binary trees, write a function to check if they is equal or not.

The binary trees is considered equal if they is structurally identical and the nodes has the same value.

2. Solution 1

Class Solution {Public:bool Issametree (TreeNode *p, TreeNode *q) {if (!p &&!q) return true;        else if (!p && q) return false;        else if (P &&!q) return false;            else {if (p->val! = Q->val) return false;                else {queue<treenode*> LQ;                Queue<treenode*> RQ;                Lq.push (P);                Rq.push (q);                    while (!lq.empty () &&!rq.empty ()) {treenode* Lfront = Lq.front ();                    treenode* Rfront = Rq.front ();                    Lq.pop ();                    Rq.pop (); if (!lfront->left &&!rfront->left);//null else if (!lfront->le                    FT && Rfront->left) return false; else if (Lfront->left &&!rfront-&Gt;left) return false;                            else {if (lfront->left->val! = rfront->left->val)                        return false;                            else {Lq.push (lfront->left);                        Rq.push (Rfront->left); }} if (!lfront->right &&!rfront->right);//Nu                    ll else if (!lfront->right && rfront->right) return false;                    else if (lfront->right &&!rfront->right) return false;                            else {if (lfront->right->val! = rfront->right->val)                        return false; else {Lq.push (lfront->right);                        Rq.push (Rfront->right);            }}} return true; }        }    }};

ideas: Very simple, breadth traversal can be judged more cumbersome, to the left and right node values are the same.

3. Solution 2

Class Solution {public:    bool Issametree (TreeNode *p, TreeNode *q) {        if (p = = NULL && q = = null) return true; else if (p = = NULL | | q = NULL) return False;bool islefttreesame = Issametree (P->left, q->left); bool Isrighttreesame = Issametree (p->right,q->right); return p->val = = Q->val && islefttreesame && isrighttreesame;    }};

Idea: or recursion, relatively slow.

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Leetcode same Tree