lurenaa的博客

😔失败1

  不可以重载map的比较函数，因为map的实现是红黑树，用于红黑树排序比较。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
#include <memory>
#include <iostream>
#include <vector>
#include <map>
using namespace std;

 struct TreeNode {
     int val;
     TreeNode *left;
     TreeNode *right;
     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};
 
class Solution {
public:
    struct Cmp {
        bool compr(const TreeNode* lhs, const TreeNode* rhs) const {
            if (!lhs && !rhs)
                return true;
            if ((!lhs && rhs) || (lhs && !rhs))
                return false;
            bool v = lhs->val == rhs->val;
            if (!v)
                return false;
            bool v1 = compr(lhs->left, rhs->left);
            if (!v1)
                return false;
            bool v2 = compr(lhs->right, rhs->right);
            if (!v2)
                return false;
        }
        bool operator()(const TreeNode* lhs, const TreeNode* rhs) const {
            return compr(lhs, rhs);
        }
    };
    vector<TreeNode*> findDuplicateSubtrees(TreeNode* root) {
        map<TreeNode*, int, Cmp> st;
        vector<TreeNode*> vec;
        dg(root, st, vec);
        return vec;
    }
    void dg(TreeNode* h, map<TreeNode*, int, Cmp>& st, vector<TreeNode*>& vec)
    {
        if (!h)
            return;
        dg(h->left, st, vec);
        dg(h->right, st, vec);
        size_t ct = st.count(h);
        if (ct > 0) {
            if (st.at(h) == 1) {
                cout << "i" << endl;
                vec.push_back(h);
            }
            st.at(h) += 1;
            cout << "t" << endl;
        }
        else {
            st.insert({ h, 1 });
            cout << "f" << endl;
        }
    }
};
int main()
{
    TreeNode* root = new TreeNode(1);
    root->left = new TreeNode(2);
    root->right = new TreeNode(3);
    root->left->left = new TreeNode(4);
    root->right->left = new TreeNode(2);
    root->right->right = new TreeNode(4);
    root->right->left->left = new TreeNode(4);
    Solution().findDuplicateSubtrees(root);
}

😍序列化

  序列化成字符串之后再来比较。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
class Solution {
public:
    vector<TreeNode*> findDuplicateSubtrees(TreeNode* root) {
        map<string, int> st;
        vector<TreeNode*> vec;
        string s;
        dg(root, st, vec, s);
        return vec;
    }
    void dg(TreeNode* h, map<string, int>& st, vector<TreeNode*>& vec, string& s) 
    {
        if(!h)
            return ;
        dg(h->left, st, vec, s);
        dg(h->right, st, vec, s);
        s.clear();
        seril(h, s);
        if(st.count(s)) {
            if(st.at(s) == 1) {
                // cout << "i" << endl;
                vec.push_back(h);
            }
            st.at(s) += 1;
            // cout << "t" << endl;
        } else {
            st.insert({s, 1});
            // cout << "f" << endl;
        }
    }
    void seril(TreeNode* h,string& s) 
    {   
        if(!h) {
            s += "@#";
            return ;
        }
        s += to_string(h->val) + '#';
        seril(h->left, s);
        seril(h->right, s);
    }
};

Accepted

168/168 cases passed (684 ms)

Your runtime beats 5.25 % of cpp submissions

Your memory usage beats 15.17 % of cpp submissions (54.5 MB)


 上一页

LeetCode