20240604 Yawn Sean's submission for CF1133F2

daily_problems/2024/06/0604/personal_submission/cf1133f2_yawn_sean.cpp

@@ -0,0 +1,71 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+signed main()
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(0);
+    cout.tie(0);
+
+    int n, m, d;
+    cin >> n >> m >> d;
+
+    vector<int> u(m), v(m), to1;
+    for (int i = 0; i < m; i ++) {
+        cin >> u[i] >> v[i], u[i] --, v[i] --;
+        if (u[i] == 0 || v[i] == 0)
+            to1.push_back(i);
+    }
+
+    if (to1.size() < d) {
+        cout << "NO\n";
+        return 0;
+    }
+
+    dsu dsu1(n), dsu2(n);
+
+    for (int i = 0; i < m; i ++) 
+        if (u[i] != 0 && v[i] != 0)
+            dsu1.merge(u[i], v[i]);
+
+    int cnt = 0, k = to1.size();
+    vector<int> components(n), used(k);
+
+    for (int i = 0; i < m; i ++) {
+        int x = dsu1.leader(u[i] ? u[i] : v[i]);
+        cnt -= components[x];
+        components[x] = 1;
+        cnt += components[x];
+    }
+
+    if (d < cnt) {
+        cout << "NO\n";
+        return 0;
+    }
+    cout << "YES\n";
+
+    for (int i = 0; i < k; i ++) {
+        int x = u[to1[i]] ? u[to1[i]] : v[to1[i]];
+        if (components[dsu1.leader(x)]) {
+            components[dsu1.leader(x)] = 0;
+            used[i] = 1;
+            d --;
+            dsu2.merge(x, 0);
+            cout << 1 << ' ' << x + 1 << '\n';
+        }
+    }
+
+    for (int i = 0; i < k; i ++) {
+        int x = u[to1[i]] ? u[to1[i]] : v[to1[i]];
+        if (used[i] == 0 && d > 0) {
+            d --;
+            dsu2.merge(x, 0);
+            cout << 1 << ' ' << x + 1 << '\n';
+        }
+    }
+
+    for (int i = 0; i < m; i ++) 
+        if (u[i] != 0 && v[i] != 0 && dsu2.merge(u[i], v[i]))
+            cout << u[i] + 1 << ' ' << v[i] + 1 << '\n';
+    return 0;
+}