[20251209] BOJ / G4 / 자벌레 세기 / 권혁준

khj20006/202512/09 BOJ G4 자벌레 세기.md

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+```cpp
+#include <bits/stdc++.h>
+using namespace std;
+using ll = long long;
+
+int N;
+ll deg[300001]{};
+vector<pair<int, int>> edges;
+
+int main(){
+    cin.tie(0)->sync_with_stdio(0);
+
+    cin>>N;
+    edges.resize(N-1);
+    for(auto &[a,b] : edges) {
+        cin>>a>>b;
+        deg[a]++;
+        deg[b]++;
+    }
+
+    ll ans = 0;
+    for(auto [a,b] : edges) if(min(deg[a], deg[b]) >= 3) {
+        ans += ((deg[a] - 1) * (deg[a] - 2) / 2) * ((deg[b] - 1) * (deg[b] - 2) / 2);
+    }
+    cout<<ans;
+
+}
+```