題目

100. 相同的樹

我的思路實現

/**
 * 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:
    bool isSameTree(TreeNode* p, TreeNode* q) {
        vector<TreeNode *> Q1;
        vector<TreeNode *> Q2;
        Q1.push_back(p);
        Q2.push_back(q);
        TreeNode * temp1;
        TreeNode * temp2;
        while(!Q1.empty())
        {
            temp1 
 
= Q1.front();
            Q1.erase(Q1.begin());
            if(Q2.empty()) return false;
            temp2 = Q2.front();
            Q2.erase(Q2.begin());
            if(temp1==NULL && temp2==NULL)
            {
                continue;
            }
            else if(temp1==NULL||temp2==NULL)
            {
                
 
return false;
            }
            else if(temp1->val==temp2->val)
            {
                Q1.push_back(temp1->left);
                Q2.push_back(temp2->left);
                Q1.push_back(temp1->right);
                Q2.push_back(temp2->right);
            }
            else{
                return false;
            }
        }
        if(Q2.empty())
            return true;
            else return false;
    }
};
/*
兩棵樹同時遍歷，比較
1.深度優先，遞迴
class Solution {
public:
    bool compare(TreeNode *t1,TreeNode *t2)
    {
        if(t1==NULL && t2==NULL)
        {
            return true;
        }
        else if(t1==NULL ||t2==NULL)
        {
            return false;
        }
        else if(t1->val!=t2->val)
        {
            return false;
        }
        else
            if(t1->val==t2->val)
        {
            if(compare(t1->left,t2->left))
                return compare(t1->right,t2->right);
            else return false;
        }
        return false;

    }
    bool isSameTree(TreeNode* p, TreeNode* q) {
        return compare(p,q);
    }
};
2.廣度優先，佇列
class Solution {
public:
    bool isSameTree(TreeNode* p, TreeNode* q) {
        vector<TreeNode *> Q1;
        vector<TreeNode *> Q2;
        Q1.push_back(p);
        Q2.push_back(q);
        TreeNode * temp1;
        TreeNode * temp2;
        while(!Q1.empty())
        {
            temp1 = Q1.front();
            Q1.erase(Q1.begin());
            if(Q2.empty()) return false;
            temp2 = Q2.front();
            Q2.erase(Q2.begin());
            if(temp1==NULL && temp2==NULL)
            {
                continue;
            }
            else if(temp1==NULL||temp2==NULL)
            {
                return false;
            }
            else if(temp1->val==temp2->val)
            {
                Q1.push_back(temp1->left);
                Q2.push_back(temp2->left);
                Q1.push_back(temp1->right);
                Q2.push_back(temp2->right);
            }
            else{
                return false;
            }
        }
        if(Q2.empty())
            return true;
            else return false;
    }
};
*/

拓展學習