P8252 [NOI Online 2022 提高组] 讨论

https://www.luogu.com.cn/record/102566109

Luogu/P8252/P8252.cpp

@@ -0,0 +1,90 @@
+#include <iostream>
+#include <algorithm>
+#include <functional>
+#include <iterator>
+#include <unordered_set>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+struct node {
+    int id;
+    std::vector<int> v;
+
+    node(const int &_id = 0, const int &_sz = 0)
+        : id(_id), v(_sz) {}
+};
+
+void solve() {
+    int n;
+
+    cin >> n;
+
+    std::vector<node> v;
+    std::vector<int> t(n, -1);
+
+    for (int i = 1, k; i <= n; i++) {
+        cin >> k;
+
+        v.emplace_back(node(i, k));
+
+        for (int &x : v.back().v) cin >> x, x--;
+    }
+
+    std::sort(v.begin(), v.end(), [&](const node &a, const node &b) -> bool {
+        return a.v.size() > b.v.size();
+    });
+
+    for (int i = 0; i < n; i++) {
+        std::unordered_set<int> set;
+
+        for (int x : v[i].v) {
+            if (t[x] != -1) set.emplace(t[x]);
+        }
+
+        if (set.size() == 1) {
+            int id = *set.begin();
+
+            for (int x : v[i].v) {
+                if (t[x] != id) {
+                    cout << "YES" << endl
+                         << v[i].id << ' ' << v[id].id << endl;
+
+                    return;
+                }
+            }
+        } else if (set.size() > 1) {
+            int id = *set.begin();
+
+            for (int x : set) {
+                if (v[x].v.size() < v[id].v.size()) id = x;
+            }
+
+            cout << "YES" << endl
+                 << v[i].id << ' ' << v[id].id << endl;
+
+            return;
+        }
+
+        for (int x : v[i].v) {
+            t[x] = i;
+        }
+    }
+
+    cout << "NO" << endl;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int t;
+
+    cin >> t;
+
+    while (t--) solve();
+
+    return 0;
+}