using System; using System.Collections.Generic; using CompLib.Collections; using CompLib.Collections.Generic; using CompLib.Util; public class Program { // private int N; public void Solve() { var sc = new Scanner(); int n = sc.NextInt(); int[] a = sc.IntArray(); int[] b = sc.IntArray(); int[] indexOf = new int[n + 1]; for (int i = 0; i < n; i++) { indexOf[b[i]] = i; } int[] tmp = new int[n]; for (int i = 0; i < n; i++) { tmp[i] = indexOf[a[i]]; } long ans = 0; var st = new SegmentTree(n, (l, r) => l + r, 0); for (int i = 0; i < n; i++) { ans += st.Query(tmp[i], n); st[tmp[i]]++; } Console.WriteLine(ans); } public static void Main(string[] args) => new Program().Solve(); } namespace CompLib.Collections.Generic { using System; public class SegmentTree { private readonly int N; private T[] _array; private T _identity; private Func _operation; public SegmentTree(int size, Func operation, T identity) { N = 1; while (N < size) N *= 2; _identity = identity; _operation = operation; _array = new T[N * 2]; for (int i = 1; i < N * 2; i++) { _array[i] = _identity; } } /// /// A[i]をnに更新 O(log N) /// /// /// public void Update(int i, T n) { i += N; _array[i] = n; while (i > 1) { i /= 2; _array[i] = _operation(_array[i * 2], _array[i * 2 + 1]); } } private T Query(int left, int right, int k, int l, int r) { if (r <= left || right <= l) { return _identity; } if (left <= l && r <= right) { return _array[k]; } return _operation(Query(left, right, k * 2, l, (l + r) / 2), Query(left, right, k * 2 + 1, (l + r) / 2, r)); } /// /// A[left] op A[left+1] ... op A[right-1]を求める /// /// /// /// public T Query(int left, int right) { return Query(left, right, 1, 0, N); } public T this[int i] { set { Update(i, value); } get { return _array[i + N]; } } } } namespace CompLib.Util { using System; using System.Linq; class Scanner { private string[] _line; private int _index; private const char Separator = ' '; public Scanner() { _line = new string[0]; _index = 0; } public string Next() { if (_index >= _line.Length) { string s; do { s = Console.ReadLine(); } while (s.Length == 0); _line = s.Split(Separator); _index = 0; } return _line[_index++]; } public string ReadLine() { _index = _line.Length; return Console.ReadLine(); } public int NextInt() => int.Parse(Next()); public long NextLong() => long.Parse(Next()); public double NextDouble() => double.Parse(Next()); public decimal NextDecimal() => decimal.Parse(Next()); public char NextChar() => Next()[0]; public char[] NextCharArray() => Next().ToCharArray(); public string[] Array() { string s = Console.ReadLine(); _line = s.Length == 0 ? new string[0] : s.Split(Separator); _index = _line.Length; return _line; } public int[] IntArray() => Array().Select(int.Parse).ToArray(); public long[] LongArray() => Array().Select(long.Parse).ToArray(); public double[] DoubleArray() => Array().Select(double.Parse).ToArray(); public decimal[] DecimalArray() => Array().Select(decimal.Parse).ToArray(); } }