#13244. 「CSP2022模拟赛0913」罚抄

http://www.nfls.com.cn:10611/submission/237162

NFLSOJ/13244/13244.cpp

@@ -0,0 +1,64 @@
+// #include <iostream>
+#include <algorithm>
+#include <cstring>
+#include <fstream>
+#include <utility>
+#include <vector>
+
+// using std::cin;
+// using std::cout;
+std::ifstream cin("rewrite.in");
+std::ofstream cout("rewrite.out");
+const char endl = '\n';
+
+const int N = 5005;
+
+int n;
+long long f[N][N][2];
+bool flag = false;
+std::pair<int, int> a[N];
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n;
+
+    for (int i = 1, l, r; i <= n; i++) {
+        cin >> a[i].first >> a[i].second;
+    }
+
+    if (n % 2) {
+        flag = true;
+    } else {
+        a[++n] = std::make_pair(0, 0);
+    }
+
+    memset(f, 0x3f, sizeof(f));
+    std::sort(a + 1, a + n + 1, [&](const std::pair<int, int> &lhs, const std::pair<int, int> &rhs) -> bool { return lhs.second - lhs.first > rhs.second - rhs.first; });
+
+    f[0][0][0] = 0;
+    for (int i = 1; i <= n; i++) {
+        if (i == n || flag) {
+            for (int j = 0; j <= i; j++) {
+                f[i][j][1] = f[i - 1][j][0] + static_cast<long long>(n >> 1) * (a[i].second - a[i].first);
+            }
+        }
+
+        for (int j = 0; j <= i; j++) {
+            if (j) {
+                f[i][j][0] = std::min(f[i][j][0], f[i - 1][j - 1][0] + static_cast<long long>(j - 1) * (a[i].second - a[i].first) + a[i].second);
+                f[i][j][1] = std::min(f[i][j][1], f[i - 1][j - 1][1] + static_cast<long long>(j - 1) * (a[i].second - a[i].first) + a[i].second);
+            }
+
+            if (j != i) {
+                f[i][j][0] = std::min(f[i][j][0], f[i - 1][j][0] + static_cast<long long>(i - j - 1) * (a[i].second - a[i].first) - a[i].first);
+                f[i][j][1] = std::min(f[i][j][1], f[i - 1][j][1] + static_cast<long long>(i - j - 2) * (a[i].second - a[i].first) - a[i].first);
+            }
+        }
+    }
+
+    cout << f[n][n >> 1][1] << endl;
+
+    return 0;
+}