lotsastuff

Author: ablondal

CSES/Additional_Problems/acyclic_graph_edges.cpp

@@ -0,0 +1,24 @@
+#include <bits/stdc++.h>
+using namespace std;
+// incomplete
+#define rep(i, a, b) for(int i = a; i < (b); ++i)
+#define all(x) begin(x), end(x)
+#define sz(x) (int)(x).size()
+typedef long long ll;
+typedef pair<int, int> pii;
+typedef vector<int> vi;
+typedef vector<ll> vll;
+typedef complex<double> cd;
+
+int main() {
+	ios_base::sync_with_stdio(false);
+	cin.tie(NULL);
+	int n, m;
+	cin >> n >> m;
+	rep(i,0,m){
+		int a, b;
+		cin >> a >> b;
+		if (b < a) swap(a, b);
+		cout << a << " " << b << endl;
+	}
+}

CSES/Additional_Problems/pyramid_array.cpp

@@ -0,0 +1,41 @@
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+using namespace std;
+using namespace __gnu_pbds;
+// incomplete
+#define rep(i, a, b) for(int i = a; i < (b); ++i)
+#define all(x) begin(x), end(x)
+#define sz(x) (int)(x).size()
+typedef long long ll;
+typedef pair<int, int> pii;
+typedef vector<int> vi;
+typedef vector<ll> vll;
+typedef complex<double> cd;
+
+tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> OS;
+// Supports .order_of_key(x), counts number of elements less than x.
+// Supports .find_by_order(n), returns iterator to nth element (0-indexed)
+
+int main() {
+	ios_base::sync_with_stdio(false);
+	cin.tie(NULL);
+	int n;
+	cin >> n;
+	vector<pii> a;
+	rep(i,0,n){
+		int b;
+		cin >> b;
+		a.push_back({b, i});
+		OS.insert(i);
+	}
+	sort(all(a));
+	ll tot = 0;
+	rep(i,0,n){
+		int id = OS.order_of_key(a[i].second);
+		// cout << i << " " << min(n-i-1-id, id) << endl;
+		tot += min(n-i-1-id,id);
+		OS.erase(a[i].second);
+	}
+	cout << tot << endl;
+}