P2569 [SCOI2010]股票交易

https://www.luogu.com.cn/record/77710267

Luogu/P2569/P2569.cpp

@@ -0,0 +1,63 @@
+#include <iostream>
+#include <cstring>
+#include <deque>
+#include <tuple>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 2005;
+
+int n, m, w, f[N][N];
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    memset(f, 0xcf, sizeof(f));
+
+    cin >> n >> m >> w;
+
+    for (int i = 1; i <= n; i++) {
+        f[i][0] = 0;
+
+        int ap, bp, as, bs;
+
+        cin >> ap >> bp >> as >> bs;
+
+        // [2]: 从 0 张开始买入
+        for (int j = 0; j <= as; j++) {
+            f[i][j] = -j * ap;
+        }
+
+        // [1]: 不操作
+        for (int j = 0; j <= m; j++) {
+            f[i][j] = std::max(f[i][j], f[i - 1][j]);
+        }
+
+        if (i - w - 1 > 0) {
+            // [3]: 买入
+            std::deque<int> q1;
+            for (int j = 0; j <= m; j++) {
+                while (!q1.empty() && q1.front() < j - as) q1.pop_front();
+                while (!q1.empty() && f[i - w - 1][q1.back()] + q1.back() * ap <= f[i - w - 1][j] + j * ap) q1.pop_back();
+                q1.push_back(j);
+                f[i][j] = std::max(f[i][j], f[i - w - 1][q1.front()] - (j - q1.front()) * ap);
+            }
+
+            // [4]: 卖出
+            std::deque<int> q2;
+            for (int j = m; ~j; j--) {
+                while (!q2.empty() && q2.front() > j + bs) q2.pop_front();
+                while (!q2.empty() && f[i - w - 1][q2.back()] + q2.back() * bp <= f[i - w - 1][j] + j * bp) q2.pop_back();
+                q2.push_back(j);
+                f[i][j] = std::max(f[i][j], f[i - w - 1][q2.front()] + (q2.front() - j) * bp);
+            }
+        }
+    }
+
+    cout << f[n][0] << endl;
+
+    return 0;
+}