220724/이현동

[Week14 - LCA]/이현동/11437.cpp

@@ -0,0 +1,71 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int N, M;
+int a, b;
+queue<int> q;
+vector<int> node[50001];
+bool check[50001];
+int parent[50001];
+int depth[50001];
+
+int LCA(int u, int v)
+{
+	// v가 u보다 더 깊게 설정
+	if (depth[u] > depth[v]) swap(u, v);
+	while (depth[u] != depth[v]) v = parent[v];
+
+	// 두 노드가 같아질때 까지 위로 거슬러 올라감
+	while (u != v)
+	{
+		u = parent[u];
+		v = parent[v];
+	}
+	return u;
+}
+
+
+int main()
+{
+	ios_base::sync_with_stdio(0);
+	cin.tie(0);
+
+	cin >> N;
+
+	for (int i = 0; i < N-1; i++)
+	{
+		cin >> a >> b;
+		node[a].push_back(b);
+		node[b].push_back(a);
+	}
+
+    //root node
+	check[1] = true;
+	q.push(1);
+
+	while (!q.empty())
+	{
+		int x = q.front(); 
+		q.pop();
+
+		for (int i = 0; i < node[x].size(); i++)
+		{
+			if (!check[node[x][i]]) 
+			{
+				depth[node[x][i]] = depth[x] + 1; // 깊이 +1
+				check[node[x][i]] = true; // 방문표시
+				parent[node[x][i]] = x; // 부모노드 입력
+				q.push(node[x][i]); // 큐에 추가
+			}
+		}
+	}
+
+	cin >> M;
+
+	for (int i = 0; i < M; i++)
+	{
+		cin >> a >> b;
+		cout << LCA(a, b) << '\n';
+	}
+
+}

[Week14 - LCA]/이현동/11812.cpp

@@ -0,0 +1,38 @@
+#include <bits/stdc++.h>
+using namespace std;
+typedef long long ll;
+
+ll N;
+int K, Q;
+ll u, v;
+
+int main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+    cout.tie(0);
+    cin >> N >> K >> Q;
+
+    for (int i = 0; i < Q;i++){
+        cin >> u >> v;
+        ll depth = 0;
+        if(K == 1)
+            depth = abs(u - v);
+        else{
+            while(u != v){
+                // cout << "u, v :"  << u << ' ' <<  v << '\n';
+                if (u > v){
+                    u = (u - 2) / K + 1;
+                }else{
+                    v = (v - 2) / K + 1;
+                }
+                ++depth;
+            }
+        }
+        // cout << u << ' ' <<  v << '\n';
+        cout << depth << '\n';
+        // cout << "----------\n";
+    }
+
+        return 0;
+}