P2339 [USACO04OPEN]Turning in Homework G

https://www.luogu.com.cn/record/85983366

Luogu/P2339/P2339.cpp

@@ -0,0 +1,54 @@
+#include <iostream>
+#include <algorithm>
+#include <cmath>
+#include <cstring>
+#include <limits>
+#include <utility>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1005;
+
+int c, h, b, f[N][N][2], ans = std::numeric_limits<int>::max();
+std::pair<int, int> a[N];
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    memset(f, 0x3f, sizeof(f));
+
+    cin >> c >> h >> b;
+
+    for (int i = 1; i <= c; i++) {
+        cin >> a[i].first >> a[i].second;
+    }
+
+    std::sort(a + 1, a + 1 + c);
+
+    f[0][c][0] = f[0][c][1] = 0;
+
+    for (int i = 1; i <= c; i++) {
+        for (int j = c; j >= i; j--) {
+            f[i][j][0] = std::min({
+                std::max(f[i - 1][j][0] + a[i].first - a[i - 1].first, a[i].second),
+                std::max(f[i][j + 1][1] + a[j + 1].first - a[i].first, a[i].second),
+            });
+
+            f[i][j][1] = std::min({
+                std::max(f[i - 1][j][0] + a[j].first - a[i - 1].first, a[j].second),
+                std::max(f[i][j + 1][1] + a[j + 1].first - a[j].first, a[j].second),
+            });
+        }
+    }
+
+    for (int i = 1; i <= c; i++) {
+        ans = std::min(ans, std::min(f[i][i][0], f[i][i][1]) + std::abs(b - a[i].first));
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}