P7561 [JOISC 2021 Day2] 道路の建設案 (Road Construction)

https://www.luogu.com.cn/record/101118415

Luogu/P7561/P7561.cpp

@@ -0,0 +1,96 @@
+#include <iostream>
+#include <algorithm>
+#include <queue>
+#include <set>
+#include <utility>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const long long INF = 0x3f3f3f3f'3f3f3f3f;
+
+int n, k;
+std::vector<std::pair<long long, long long>> points;
+
+bool check(long long x) {
+    int cnt = 0;
+    std::queue<std::pair<long long, long long>> q;
+    std::set<std::pair<long long, long long>> set;
+
+    for (auto o : points) {
+        while (!q.empty() && q.front().first + x < o.first) {
+            set.erase({q.front().second, q.front().first});
+            q.pop();
+        }
+
+        cnt += std::distance(set.lower_bound({o.second - x, -INF}), set.upper_bound({o.second + x, INF}));
+
+        if (cnt >= k) return true;
+
+        set.emplace(o.second, o.first);
+        q.emplace(o);
+    }
+
+    return false;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> k;
+
+    for (int i = 1, x, y; i <= n; i++) {
+        cin >> x >> y;
+
+        points.emplace_back(x + y, x - y);
+    }
+
+    std::sort(points.begin(), points.end());
+
+    long long l = 0,
+              r = INF,
+              res;
+
+    while (l <= r) {
+        long long mid = (l + r) >> 1;
+
+        if (check(mid)) {
+            res = mid;
+            r = mid - 1;
+        } else {
+            l = mid + 1;
+        }
+    }
+
+    std::vector<long long> ans;
+    std::queue<std::pair<long long, long long>> q;
+    std::set<std::pair<long long, long long>> set;
+
+    for (auto o : points) {
+        while (!q.empty() && q.front().first + res - 1 < o.first) {
+            set.erase({q.front().second, q.front().first});
+            q.pop();
+        }
+
+        std::transform(
+            set.lower_bound({o.second - res + 1, -INF}),
+            set.upper_bound({o.second + res - 1, INF}),
+            std::back_inserter(ans),
+            [&](const std::pair<long long, long long>& item) -> long long {
+                return std::max(std::abs(item.first - o.second), o.first - item.second);
+            });
+
+        set.emplace(o.second, o.first);
+        q.emplace(o);
+    }
+
+    std::sort(ans.begin(), ans.end());
+    ans.resize(k, res);
+
+    for (auto x : ans) cout << x << endl;
+
+    return 0;
+}