E - Yet Another Interval Graph Problem

https://codeforces.com/gym/103627/submission/175842546

Gym/103627/E/E.cpp

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+#include <iostream>
+#include <algorithm>
+#include <iterator>
+#include <queue>
+#include <utility>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 2505;
+
+int n, k, s[N], e[N], w[N];
+long long f[N << 1], sum;
+std::vector<int> nums;
+std::vector<std::pair<int, int>> g[N << 1];
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> k;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> s[i] >> e[i] >> w[i];
+
+        nums.emplace_back(s[i]);
+        nums.emplace_back(e[i]);
+        sum += w[i];
+    }
+
+    std::sort(nums.begin(), nums.end());
+    nums.erase(std::unique(nums.begin(), nums.end()), nums.end());
+
+    for (int i = 1; i <= n; i++) {
+        s[i] = std::distance(nums.begin(), std::lower_bound(nums.begin(), nums.end(), s[i])) + 1;
+        e[i] = std::distance(nums.begin(), std::lower_bound(nums.begin(), nums.end(), e[i])) + 1;
+
+        g[s[i]].emplace_back(e[i], w[i]);
+    }
+
+    for (int i = 1; i <= nums.size(); i++) {
+        std::priority_queue<int, std::vector<int>, std::greater<>> q;
+        long long res = 0;
+
+        for (int j = i; j; j--) {
+            for (auto e : g[j]) {
+                if (e.first <= i) {
+                    if (q.size() < k) {
+                        q.emplace(e.second);
+                        res += e.second;
+                    } else if (q.top() < e.second) {
+                        res += e.second - q.top();
+                        q.pop();
+                        q.emplace(e.second);
+                    }
+                }
+            }
+
+            f[i] = std::max(f[i], f[j - 1] + res);
+        }
+    }
+
+    cout << sum - f[nums.size()] << endl;
+
+    return 0;
+}