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Problem 136

Easy

1 · Worked examples

0 / 3

Type an input and write what you think is the output . Each problem is converted to Web Assembly, so any possible input will show the corresponding output. Only correct predictions count.

solution()
returns

2 · Which problem is it?

Locked until you have predicted 3 outputs correctly.

The accepted solution

1struct Node {
2 int val;
3 Node* left;
4 Node* right;
5};
6
7Node* build(const vector<optional<int>>& level) {
8
9 if (level.empty() || !level[0]) {
10 return nullptr;
11 }
12
13 Node* root = new Node{*level[0], nullptr, nullptr};
14
15 queue<Node*> q;
16 q.push(root);
17
18 int i = 1;
19 int n = level.size();
20
21 while (!q.empty() && i < n) {
22
23 Node* node = q.front();
24 q.pop();
25
26 if (level[i]) {
27 node->left = new Node{*level[i], nullptr, nullptr};
28 q.push(node->left);
29 }
30
31 i++;
32
33 if (i < n && level[i]) {
34 node->right = new Node{*level[i], nullptr, nullptr};
35 q.push(node->right);
36 }
37
38 i++;
39 }
40
41 return root;
42}
43
44bool alike(Node* a, Node* b) {
45
46 if (!a || !b) {
47 return a == b;
48 }
49
50 if (a->val != b->val) {
51 return false;
52 }
53
54 bool leftSame = alike(a->left, b->left);
55 bool rightSame = alike(a->right, b->right);
56
57 return leftSame && rightSame;
58}
59
60bool solution(const vector<optional<int>>& first,
61 const vector<optional<int>>& second) {
62
63 Node* a = build(first);
64 Node* b = build(second);
65
66 return alike(a, b);
67}

Names have been stripped. The signature is the only clue you get for free. Compiled as C++20 with the standard headers and using namespace std; already in scope.