#1811. 【2017.3 长乐省选集训 Day10 T1】圆圈游戏

https://sjzezoj.com/submission/66472

S2OJ/1811/1811.cpp

@@ -0,0 +1,104 @@
+#include <iostream>
+#include <algorithm>
+#include <cmath>
+#include <set>
+#include <tuple>
+#include <utility>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e5 + 5;
+
+int n, base, fa[N];
+std::tuple<int, int, int, int> c[N];
+std::vector<std::tuple<int, int, bool>> p;
+std::vector<int> g[N];
+
+double pos(int id, bool p) {
+    int x, y, r;
+
+    std::tie(x, y, r, std::ignore) = c[id];
+
+    double d = std::sqrt(std::pow(r, 2) - std::pow(base - x, 2));
+
+    if (p) return y - d;
+    return y + d;
+}
+
+std::multiset<std::pair<int, bool>, bool (*)(std::pair<int, bool>, std::pair<int, bool>)> set{[](std::pair<int, bool> lhs, std::pair<int, bool> rhs) {
+    return pos(lhs.first, lhs.second) > pos(rhs.first, rhs.second);
+}};
+
+int dfs(int u) {
+    int res = 0;
+
+    for (int v : g[u]) {
+        res += dfs(v);
+    }
+
+    return std::max(res, std::get<3>(c[u]));
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n;
+
+    for (int i = 1, x, y, r, w; i <= n; i++) {
+        cin >> x >> y >> r >> w;
+
+        c[i] = std::make_tuple(x, y, r, w);
+        p.emplace_back(x - r, i, false);
+        p.emplace_back(x + r, i, true);
+    }
+
+    std::sort(p.begin(), p.end(), [](std::tuple<int, int, bool> lhs, std::tuple<int, int, bool> rhs) {
+        int x1, x2;
+        bool op1, op2;
+
+        std::tie(x1, std::ignore, op1) = lhs;
+        std::tie(x2, std::ignore, op2) = rhs;
+
+        return x1 == x2 ? op1 > op2 : x1 < x2;
+    });
+
+    for (auto o : p) {
+        int x, id, op;
+
+        std::tie(x, id, op) = o;
+
+        if (op) {
+            set.erase({id, 0});
+            set.erase({id, 1});
+        } else {
+            base = x;
+            set.emplace(id, 0);
+
+            auto it = set.find({id, 0});
+
+            if (it != set.begin()) {
+                int id2;
+                bool op2;
+
+                std::tie(id2, op2) = *std::prev(it);
+
+                if (op2) fa[id] = fa[id2];
+                else fa[id] = id2;
+            }
+
+            set.emplace(id, 1);
+        }
+    }
+
+    for (int i = 1; i <= n; i++) {
+        g[fa[i]].push_back(i);
+    }
+
+    cout << dfs(0) << endl;
+
+    return 0;
+}