D - Buy Low Sell High

https://codeforces.com/contest/865/submission/175146415

Codeforces/865/D/D.cpp

@@ -0,0 +1,39 @@
+#include <iostream>
+#include <functional>
+#include <queue>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 3e5 + 5;
+
+int n, p[N];
+long long ans;
+std::priority_queue<int, std::vector<int>, std::greater<>> q;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> p[i];
+    }
+
+    for (int i = 1; i <= n; i++) {
+        if (!q.empty() && q.top() < p[i]) {
+            ans += p[i] - q.top();
+            q.pop();
+            q.emplace(p[i]);
+        }
+
+        q.emplace(p[i]);
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}