[20250429] BOJ / P2 / 민혁이의 게임 파티 / 권혁준

Author: oncsr

khj20006/202504/29 BOJ P2 민혁이의 게임 파티.md

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+```cpp
+#include <iostream>
+#include <numeric>
+#include <set>
+using namespace std;
+
+int N, M, Q;
+multiset<int> S[100001]{};
+int A[100001]{}, C[100001]{}, r[100001]{}, ans[100001]{};
+
+int f(int x) { return x == r[x] ? x : r[x] = f(r[x]); }
+
+int main() {
+	cin.tie(0)->sync_with_stdio(0);
+
+	cin >> N >> M >> Q;
+	for (int i = 1; i <= N; i++) {
+		cin >> A[i];
+		S[i].insert(A[i]);
+		C[A[i]]++;
+	}
+	for (int i = 1; i <= M; i++) ans[i] = C[i] == 1 ? 0 : -1;
+
+	iota(r, r + N + 1, 0);
+
+	for (int a, b, t = 1; Q--; t++) {
+		cin >> a >> b;
+		int x = f(a), y = f(b);
+		if (x == y) continue;
+		if (S[x].size() > S[y].size()) swap(x, y);
+		for (int j : S[x]) {
+			S[y].insert(j);
+			if (C[j] == S[y].count(j) && ans[j] < 0) ans[j] = t;
+		}
+		S[x] = multiset<int>();
+		r[x] = y;
+	}
+
+	for (int i = 1; i <= M; i++) cout << ans[i] << '\n';
+
+}
+```