P4269 [USACO18FEB]Snow Boots G

https://www.luogu.com.cn/record/86653460

Luogu/P4269/P4269.cpp

@@ -0,0 +1,86 @@
+#include <iostream>
+#include <algorithm>
+#include <deque>
+#include <functional>
+#include <tuple>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+int n, b;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> b;
+
+    std::vector<int> a(n), d(n);
+
+    for (int &x : a) cin >> x;
+
+    std::vector<std::pair<int, int>> shoes;
+
+    for (int i = 0, s; i < b; i++) {
+        cin >> s >> d[i];
+
+        shoes.emplace_back(i, s);
+    }
+
+    std::vector<int> ans(n);
+
+    auto solve = [&](int ql, int qr, int l, int r, auto &&solve) -> void {
+        if (ql > qr || l > r) return;
+
+        if (l == r) {
+            for (int i = ql; i <= qr; i++) {
+                ans[shoes[i].first] = l;
+            }
+
+            return;
+        }
+
+        int mid = l + r >> 1;
+        std::deque<int> q{0};
+        std::vector<int> f(n);
+
+        for (int i = 1; i < n; i++) {
+            while (!q.empty() && i - q.front() > mid) q.pop_front();
+            f[i] = std::max(a[i], f[q.front()]);
+            while (!q.empty() && f[i] <= f[q.back()]) q.pop_back();
+            q.push_back(i);
+        }
+
+        if (shoes[ql].second < *f.rbegin()) {
+            solve(ql, qr, mid + 1, r, solve);
+        } else if (shoes[qr].second >= *f.rbegin()) {
+            solve(ql, qr, l, mid, solve);
+        } else {
+            int pos = std::lower_bound(
+                          shoes.begin() + ql,
+                          shoes.begin() + qr + 1,
+                          std::make_pair(0, *f.rbegin()),
+                          [](auto &&lhs, auto &&rhs) -> bool {
+                              return lhs.second >= rhs.second;
+                          })
+                    - shoes.begin();
+
+            solve(ql, pos - 1, l, mid, solve);
+            solve(pos, qr, mid + 1, r, solve);
+        }
+    };
+
+    std::sort(shoes.begin(), shoes.end(), [](auto &&lhs, auto &&rhs) -> bool {
+        return lhs.second > rhs.second;
+    });
+
+    solve(0, b - 1, 1, n, solve);
+
+    for (int i = 0; i < b; i++) {
+        cout << (ans[i] <= d[i]) << endl;
+    }
+
+    return 0;
+}