結果

問題 No.1300 Sum of Inversions
ユーザー EmKjp
提出日時 2020-12-02 21:08:54
言語 C#(csc)
(csc 3.9.0)
結果
AC  
実行時間 440 ms / 2,000 ms
コード長 11,875 bytes
コンパイル時間 1,095 ms
コンパイル使用メモリ 120,848 KB
実行使用メモリ 47,328 KB
最終ジャッジ日時 2024-09-13 10:43:48
合計ジャッジ時間 12,988 ms
ジャッジサーバーID
(参考情報)
judge2 / judge5
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
sample AC * 3
other AC * 34
権限があれば一括ダウンロードができます
コンパイルメッセージ
Microsoft (R) Visual C# Compiler version 3.9.0-6.21124.20 (db94f4cc)
Copyright (C) Microsoft Corporation. All rights reserved.

ソースコード

diff #
プレゼンテーションモードにする

using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Text;
using System.Linq;
using E = System.Linq.Enumerable;
using System.Threading;
internal partial class Solver {
public void Run() {
var n = ni();
var a = ni(n);
Array.Reverse(a);
var d = new IndexDictionary<int>(a);
var leftNum = new BinaryIndexTree(d.Count);
var rightNum = new BinaryIndexTree(d.Count);
var leftSum = new BinaryIndexTree(d.Count);
var rightSum = new BinaryIndexTree(d.Count);
for (int i = 0; i < n; i++) {
rightSum.Add(d.IndexOf(a[i]), a[i]);
rightNum.Add(d.IndexOf(a[i]), 1);
}
ModInt.SetMod998244353();
ModInt ans = 0;
for (int i = 0; i < n; i++) {
var index = d.IndexOf(a[i]);
rightNum.Add(index, -1);
rightSum.Add(index, -a[i]);
ModInt leftN = leftNum.Sum(0, index);
ModInt rightN = rightNum.Sum(index + 1, d.Count);
ans += leftN * rightN * a[i];
ans += leftSum.Sum(0, index) * rightN;
ans += rightSum.Sum(index + 1, d.Count) * leftN;
leftNum.Add(index, 1);
leftSum.Add(index, a[i]);
}
cout.WriteLine(ans);
}
}
public class IndexDictionary<T> {
private readonly Dictionary<T, int> _toIndex;
private readonly T[] _array;
public IndexDictionary(IEnumerable<T> source) : this(source, Comparer<T>.Default.Compare) { }
public IndexDictionary(IEnumerable<T> source, Comparison<T> comparison) {
_array = source.Distinct().ToArray();
Array.Sort(_array, comparison);
_toIndex = new Dictionary<T, int>(_array.Length);
int index = -1;
foreach (var x in _array) {
_toIndex[x] = ++index;
}
}
public int Count { get { return _array.Length; } }
public T this[int index] { get { return _array[index]; } }
public int IndexOf(T value) { return _toIndex[value]; }
public T[] ToArray() {
return _array.ToArray();
}
}
public class BinaryIndexTree {
private readonly long[] array;
public BinaryIndexTree(int size) {
array = new long[size];
}
public long Sum(int begin, int end) {
if (begin != 0) {
return Sum(0, end) - Sum(0, begin);
}
long val = 0;
end--;
for (; end >= 0; end = (end & (end + 1)) - 1) {
val += array[end];
}
return val;
}
public void Add(int k, long val) {
for (; k < array.Length; k |= k + 1) {
array[k] += val;
}
}
/// <summary>return min pos where sum(A[0] .. A[pos]) >= w</summary>
public int LowerBound(long w) {
if (w <= 0) {
return 0;
}
int x = 0, k = 1, N = array.Length;
while ((k << 1) <= N) {
k <<= 1;
}
for (; k > 0; k >>= 1) {
if (x + k - 1 < N && array[x + k - 1] < w) {
w -= array[x + k - 1];
x += k;
}
}
return x;
}
}
public partial struct ModInt : IEquatable<ModInt> {
private static int mod = 0;
private long _value;
public ModInt(long x) {
_value = x;
Normalize();
}
private static long RegularMod(long x, int mod) {
if (x >= mod) {
if (x < 2 * mod) {
return x - mod;
}
return x % mod;
}
if (x >= 0) {
return x;
}
x = mod - RegularMod(-x, mod);
return x == mod ? 0 : x;
}
public static int SetModValue(int m) {
return mod = m;
}
public static int SetMod998244353() { return SetModValue(998244353); }
public static int SetMod1000000007() { return SetModValue(1000000007); }
private void Normalize() {
_value = RegularMod(_value, mod);
}
public override string ToString() {
return _value.ToString(CultureInfo.InvariantCulture);
}
public int ToInt() {
return (int)_value;
}
public static bool operator ==(ModInt c1, ModInt c2) {
return c1._value == c2._value;
}
public static bool operator !=(ModInt c1, ModInt c2) {
return !(c1 == c2);
}
public static ModInt operator +(ModInt x, ModInt y) {
return new ModInt(x._value + y._value);
}
public static ModInt operator -(ModInt x, ModInt y) {
return new ModInt(x._value - y._value);
}
public static ModInt operator -(ModInt x) {
return new ModInt(-x._value);
}
public static ModInt operator *(ModInt x, ModInt y) {
return new ModInt(x._value * y._value);
}
public static ModInt operator /(ModInt x, ModInt y) {
return new ModInt(x._value * Inverse(y._value, mod));
}
public static ModInt operator ++(ModInt x) {
return x + 1;
}
public static ModInt operator --(ModInt x) {
return x - 1;
}
public static ModInt Pow(ModInt x, long n) {
ModInt r = 1;
while (n > 0) {
if ((n & 1) != 0) {
r *= x;
}
x *= x;
n >>= 1;
}
return r;
}
private static long ExtendedGcd(long a, long b, out long x, out long y) {
if (b == 0) {
x = 1; y = 0;
return a;
} else {
var d = ExtendedGcd(b, a % b, out y, out x);
y -= a / b * x;
return d;
}
}
private static long Inverse(long a, long mod) {
long x = 0, y = 0;
if (ExtendedGcd(a, mod, out x, out y) == 1) {
return (x + mod) % mod;
} else {
throw new Exception("Invalid inverse " + a + " " + mod);
}
}
public static implicit operator ModInt(long x) {
return new ModInt(x);
}
public override bool Equals(object obj) {
if (obj == null) {
return false;
}
return _value.Equals(((ModInt)obj)._value);
}
public override int GetHashCode() {
return _value.GetHashCode();
}
public bool Equals(ModInt other) {
return _value.Equals(other._value);
}
object ToDump() { return _value; }
}
// PREWRITEN CODE BEGINS FROM HERE
static public class StringExtensions {
static public string JoinToString<T>(this IEnumerable<T> source, string separator = " ") {
return string.Join(separator, source);
}
}
internal partial class Solver : Scanner {
static readonly int? StackSizeInMebiByte = null; //50;
public static void StartAndJoin(Action action, int maxStackSize) {
var thread = new Thread(new ThreadStart(action), maxStackSize);
thread.Start();
thread.Join();
}
public static void Main() {
#if LOCAL
byte[] inputBuffer = new byte[1000000];
var inputStream = Console.OpenStandardInput(inputBuffer.Length);
using (var reader = new StreamReader(inputStream, Console.InputEncoding, false, inputBuffer.Length)) {
Console.SetIn(reader);
new Solver(Console.In, Console.Out).Run();
}
#else
Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false });
if (StackSizeInMebiByte.HasValue) {
StartAndJoin(() => new Solver(Console.In, Console.Out).Run(), StackSizeInMebiByte.Value * 1024 * 1024);
} else {
new Solver(Console.In, Console.Out).Run();
}
Console.Out.Flush();
#endif
}
#pragma warning disable IDE0052
private readonly TextReader cin;
private readonly TextWriter cout;
private readonly TextWriter cerr;
#pragma warning restore IDE0052
public Solver(TextReader reader, TextWriter writer)
: base(reader) {
cin = reader;
cout = writer;
cerr = Console.Error;
}
public Solver(string input, TextWriter writer)
: this(new StringReader(input), writer) {
}
#pragma warning disable IDE1006
#pragma warning disable IDE0051
private int ni() { return NextInt(); }
private int[] ni(int n) { return NextIntArray(n); }
private long nl() { return NextLong(); }
private long[] nl(int n) { return NextLongArray(n); }
private double nd() { return NextDouble(); }
private double[] nd(int n) { return NextDoubleArray(n); }
private string ns() { return Next(); }
private string[] ns(int n) { return NextArray(n); }
#pragma warning restore IDE1006
#pragma warning restore IDE0051
}
#if DEBUG
internal static class LinqPadExtension {
public static string TextDump<T>(this T obj) {
if (obj is IEnumerable) return (obj as IEnumerable).Cast<object>().JoinToString().Dump();
else return obj.ToString().Dump();
}
public static T Dump<T>(this T obj) {
return LINQPad.Extensions.Dump(obj);
}
}
#endif
public class Scanner {
private readonly TextReader Reader;
private readonly CultureInfo ci = CultureInfo.InvariantCulture;
private readonly char[] buffer = new char[2 * 1024];
private int cursor = 0, length = 0;
private string Token;
private readonly StringBuilder sb = new StringBuilder(1024);
public Scanner()
: this(Console.In) {
}
public Scanner(TextReader reader) {
Reader = reader;
}
public int NextInt() { return checked((int)NextLong()); }
public long NextLong() {
var s = Next();
long r = 0;
int i = 0;
bool negative = false;
if (s[i] == '-') {
negative = true;
i++;
}
for (; i < s.Length; i++) {
r = r * 10 + (s[i] - '0');
#if DEBUG
if (!char.IsDigit(s[i])) throw new FormatException();
#endif
}
return negative ? -r : r;
}
public double NextDouble() { return double.Parse(Next(), ci); }
public string[] NextArray(int size) {
string[] array = new string[size];
for (int i = 0; i < size; i++) {
array[i] = Next();
}
return array;
}
public int[] NextIntArray(int size) {
int[] array = new int[size];
for (int i = 0; i < size; i++) {
array[i] = NextInt();
}
return array;
}
public long[] NextLongArray(int size) {
long[] array = new long[size];
for (int i = 0; i < size; i++) {
array[i] = NextLong();
}
return array;
}
public double[] NextDoubleArray(int size) {
double[] array = new double[size];
for (int i = 0; i < size; i++) {
array[i] = NextDouble();
}
return array;
}
public string Next() {
if (Token == null) {
if (!StockToken()) {
throw new Exception();
}
}
var token = Token;
Token = null;
return token;
}
public bool HasNext() {
if (Token != null) {
return true;
}
return StockToken();
}
private bool StockToken() {
while (true) {
sb.Clear();
while (true) {
if (cursor >= length) {
cursor = 0;
if ((length = Reader.Read(buffer, 0, buffer.Length)) <= 0) {
break;
}
}
var c = buffer[cursor++];
if (33 <= c && c <= 126) {
sb.Append(c);
} else {
if (sb.Length > 0) break;
}
}
if (sb.Length > 0) {
Token = sb.ToString();
return true;
}
return false;
}
}
}
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
0