Create mincross.cpp

1 files changed, 57 insertions, 0 deletions

diff --git a/2017/February/Platinum/mincross.cpp b/2017/February/Platinum/mincross.cpp
new file mode 100644
index 0000000..a5befd0
--- /dev/null
+++ b/2017/February/Platinum/mincross.cpp
@@ -0,0 +1,57 @@
+#include <algorithm>
+#include <iostream>
+#include <fstream>
+#include <string>
+#include <vector>
+#include <queue>
+#include <set>
+#include <map>
+#include <unordered_set>
+#include <unordered_map>
+#include <cmath>
+#include <cstring>
+using namespace std;
+typedef long long ll;
+typedef pair<int, int> ii;
+typedef vector<int> vi;
+typedef vector<ii> vii;
+constexpr auto INF = (ll)1e18;
+
+class fenwick_tree {
+private: vector<int> FT;
+public:
+	fenwick_tree(int N) { FT.assign(N + 1, 0); }
+	void update(int x, int val) { for (; x < FT.size(); x += x & -x) FT[x] += val; }
+	int query(int x) { int ret = 0; for (; x > 0; x -= x & -x) ret += FT[x]; return ret; }
+	int query(int x, int y) { return query(y) - (x == 1 ? 0 : query(x - 1)); }
+};
+
+int A[100005], B[100005], RA[100005], RB[100005];
+
+int main() {
+	ifstream cin("mincross.in");
+	ofstream cout("mincross.out");
+
+	int N;
+	cin >> N;
+	for (int i = 0; i < N; ++i) cin >> A[i];
+	for (int i = 0; i < N; ++i) cin >> B[i];
+	for (int i = 0; i < N; ++i) RA[A[i]] = i + 1;
+	for (int i = 0; i < N; ++i) RB[B[i]] = i + 1;
+
+	fenwick_tree FT(N);
+	ll cnt = 0, ans = INF;
+	for (int i = 0; i < N; ++i) {
+		cnt += FT.query(RA[B[i]], N);
+		FT.update(RA[B[i]], 1);
+	}
+	for (int i = 0; i < N; ++i) {
+		cnt += N - 2 * RA[B[i]] + 1;
+		ans = min(cnt, ans);
+	}
+	for (int i = 0; i < N; ++i) {
+		cnt += N - 2 * RB[A[i]] + 1;
+		ans = min(cnt, ans);
+	}
+	cout << ans << endl;
+}