-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
Showing
6 changed files
with
88 additions
and
1 deletion.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1 @@ | ||
| add_catch(test_minimum_height_trees test.cpp) |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,45 @@ | ||
| #pragma once | ||
|
|
||
| #include <vector> | ||
|
|
||
| // Time: O(N) | ||
| // Space: O(N) | ||
|
|
||
| class Solution { | ||
| public: | ||
| static std::vector<int> | ||
| findMinHeightTrees(int n, const std::vector<std::vector<int>> &edges) { | ||
| if (n == 1) { | ||
| return {0}; | ||
| } | ||
|
|
||
| std::vector<int> degree(n); | ||
| std::vector<std::vector<int>> adj(n); | ||
| for (const auto &edge : edges) { | ||
| const auto u = edge[0], v = edge[1]; | ||
| ++degree[u], ++degree[v]; | ||
| adj[u].push_back(v), adj[v].push_back(u); | ||
| } | ||
|
|
||
| std::vector<int> nodes; | ||
| for (int u = 0; u < n; ++u) { | ||
| if (degree[u] == 1) { | ||
| nodes.push_back(u); | ||
| } | ||
| } | ||
|
|
||
| while (n > 2) { | ||
| n -= nodes.size(); | ||
| std::vector<int> next; | ||
| for (auto u : nodes) { | ||
| for (auto v : adj[u]) { | ||
| if (--degree[v] == 1) { | ||
| next.push_back(v); | ||
| } | ||
| } | ||
| } | ||
| nodes.swap(next); | ||
| } | ||
| return nodes; | ||
| } | ||
| }; |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,39 @@ | ||
| #include <catch.hpp> | ||
|
|
||
| #include <solution.hpp> | ||
|
|
||
| TEST_CASE("Simple") { | ||
| struct TestCase { | ||
| int n; | ||
| std::vector<std::vector<int>> edges; | ||
| std::vector<int> expected; | ||
| }; | ||
|
|
||
| std::vector<TestCase> test_cases{ | ||
| { | ||
| .n = 4, | ||
| .edges{{1, 0}, {1, 2}, {1, 3}}, | ||
| .expected{1}, | ||
| }, | ||
| { | ||
| .n = 6, | ||
| .edges{{3, 0}, {3, 1}, {3, 2}, {3, 4}, {5, 4}}, | ||
| .expected{3, 4}, | ||
| }, | ||
| { | ||
| .n = 1, | ||
| .edges{}, | ||
| .expected{0}, | ||
| }, | ||
| { | ||
| .n = 3, | ||
| .edges{{0, 1}, {0, 2}}, | ||
| .expected{0}, | ||
| }, | ||
| }; | ||
|
|
||
| for (const auto &[n, edges, expected] : test_cases) { | ||
| const auto actual = Solution::findMinHeightTrees(n, edges); | ||
| REQUIRE(expected == actual); | ||
| } | ||
| } |