2024-02-15

Redish03/DFS/1167.cpp

@@ -0,0 +1,60 @@
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+vector<vector<pair<int, int>>> tree(100001);
+int max_dist = -99;
+vector<bool> path;
+int max_node = 0;
+
+void dfs(int node, int distance)
+{
+    if (path[node])
+    {
+        return;
+    }
+    if (distance > max_dist)
+    {
+        max_dist = distance;
+        max_node = node;
+    }
+    path[node] = true;
+    for (int i = 0; i < tree[node].size(); i++)
+    {
+        int nnode = tree[node][i].first;
+        int ndist = tree[node][i].second;
+        dfs(nnode, distance + ndist);
+    }
+}
+
+int main()
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    cout.tie(NULL);
+
+    int V;
+    cin >> V;
+    int a, node, dist;
+    path.resize(V + 1, false);
+
+    for (int i = 0; i < V; i++)
+    {
+        cin >> a;
+        while (true)
+        {
+            cin >> node;
+            if (node == -1)
+                break;
+            cin >> dist;
+
+            tree[a].push_back({node, dist});
+        }
+    }
+    dfs(1, 0);
+    path.assign(V + 1, false);
+    dfs(max_node, 0);
+
+    cout << max_dist;
+}

Redish03/README.md

@@ -16,5 +16,6 @@
 | 12차시 | 2024.02.03 |      DP       |      [구간 합 구하기 5](https://www.acmicpc.net/problem/11660)      | [#12](https://github.com/AlgoLeadMe/AlgoLeadMe-5/pull/47) |
 | 13차시 | 2024.02.06 | Back tracking |          [N과 M(9)](https://www.acmicpc.net/problem/15663)          | [#13](https://github.com/AlgoLeadMe/AlgoLeadMe-5/pull/52) |
 | 14차시 | 2024.02.12 | KnapSack(DP)  |        [평범한 배낭](https://www.acmicpc.net/problem/12865)         | [#14](https://github.com/AlgoLeadMe/AlgoLeadMe-5/pull/55) |
+| 15차시 | 2024.02.15 |      DFS      |         [트리의 지름](https://www.acmicpc.net/problem/1167)         | [#14](https://github.com/AlgoLeadMe/AlgoLeadMe-5/pull/55) |
 
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