P2906 [USACO08OPEN]Cow Neighborhoods G

https://www.luogu.com.cn/record/77072894

Luogu/P2906/P2906.cpp

@@ -0,0 +1,62 @@
+#include <iostream>
+#include <algorithm>
+#include <set>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e5 + 5;
+
+int n, c, fa[N], cnt[N], ans, max;
+std::pair<int, int> points[N];
+std::set<std::pair<int, int>> set;
+
+int find(int x) {
+    return fa[x] == x ? x : fa[x] = find(fa[x]);
+}
+
+inline void merge(int x, int y) {
+    fa[find(x)] = find(y);
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> c;
+
+    for (int i = 1, x, y; i <= n; i++) {
+        cin >> x >> y;
+
+        points[i] = std::make_pair(x + y, x - y);
+        fa[i] = i;
+    }
+
+    std::sort(points + 1, points + 1 + n);
+
+    set.insert(std::make_pair(points[1].second, 1));
+    for (int i = 2, l = 1; i <= n; i++) {
+        while (points[i].first - points[l].first > c) {
+            set.erase(std::make_pair(points[l].second, l));
+            l++;
+        }
+
+        auto it = set.lower_bound(std::make_pair(points[i].second, 0));
+
+        if (it != set.end() && it->first - points[i].second <= c) merge(i, it->second);
+        if (it != set.begin() && points[i].second - (--it)->first <= c) merge(i, it->second);
+
+        set.insert(std::make_pair(points[i].second, i));
+    }
+
+    for (int i = 1; i <= n; i++) {
+        if (find(i) == i) ans++;
+
+        max = std::max(max, ++cnt[find(i)]);
+    }
+
+    cout << ans << ' ' << max << endl;
+
+    return 0;
+}