P3957 [NOIP2017 普及组] 跳房子

https://www.luogu.com.cn/record/85667205

Luogu/P3957/P3957.cpp

@@ -0,0 +1,74 @@
+#include <iostream>
+#include <algorithm>
+#include <deque>
+#include <limits>
+#include <utility>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 5e5 + 5;
+const long long INF = 0x3f3f3f3f3f3f3f3f;
+
+int n, d;
+long long k, f[N], sum;
+std::pair<long long, long long> a[N];
+
+bool check(long long l, long long r) {
+    std::deque<long long> q;
+
+    for (int i = 1, j = 0; i <= n; i++) {
+        f[i] = -INF;
+
+        while (j < i && l <= a[i].first - a[j].first) {
+            if (f[j] != -INF) {
+                while (!q.empty() && f[q.back()] <= f[j]) q.pop_back();
+                q.push_back(j);
+            }
+
+            j++;
+        }
+
+        while (!q.empty() && a[i].first - a[q.front()].first > r) {
+            q.pop_front();
+        }
+
+        if (!q.empty()) {
+            f[i] = std::max(f[i], f[q.front()] + a[i].second);
+        }
+
+        if (f[i] >= k) return true;
+    }
+
+    return false;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> d >> k;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i].first >> a[i].second;
+
+        sum += a[i].second;
+    }
+
+    long long l = 0, r = INF;
+
+    while (l < r) {
+        long long mid = l + r >> 1;
+
+        if (check(std::max(d - mid, 0ll), d + mid)) {
+            r = mid;
+        } else {
+            l = mid + 1;
+        }
+    }
+
+    cout << (r == INF ? -1 : r) << endl;
+
+    return 0;
+}