結果

問題 No.1300 Sum of Inversions
ユーザー EmKjpEmKjp
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
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 33 ms
27,308 KB
testcase_01 AC 33 ms
25,212 KB
testcase_02 AC 34 ms
25,340 KB
testcase_03 AC 346 ms
44,708 KB
testcase_04 AC 310 ms
47,328 KB
testcase_05 AC 259 ms
40,228 KB
testcase_06 AC 394 ms
42,344 KB
testcase_07 AC 364 ms
45,516 KB
testcase_08 AC 440 ms
41,588 KB
testcase_09 AC 415 ms
40,584 KB
testcase_10 AC 212 ms
40,404 KB
testcase_11 AC 221 ms
40,788 KB
testcase_12 AC 328 ms
45,292 KB
testcase_13 AC 322 ms
44,160 KB
testcase_14 AC 436 ms
41,888 KB
testcase_15 AC 405 ms
40,576 KB
testcase_16 AC 331 ms
44,968 KB
testcase_17 AC 203 ms
36,400 KB
testcase_18 AC 229 ms
39,036 KB
testcase_19 AC 283 ms
46,820 KB
testcase_20 AC 303 ms
45,524 KB
testcase_21 AC 295 ms
43,228 KB
testcase_22 AC 263 ms
40,368 KB
testcase_23 AC 391 ms
41,084 KB
testcase_24 AC 270 ms
42,292 KB
testcase_25 AC 227 ms
41,068 KB
testcase_26 AC 222 ms
40,940 KB
testcase_27 AC 250 ms
43,788 KB
testcase_28 AC 406 ms
40,728 KB
testcase_29 AC 271 ms
41,300 KB
testcase_30 AC 406 ms
41,088 KB
testcase_31 AC 245 ms
42,156 KB
testcase_32 AC 270 ms
42,552 KB
testcase_33 AC 115 ms
31,308 KB
testcase_34 AC 162 ms
29,568 KB
testcase_35 AC 253 ms
43,716 KB
testcase_36 AC 274 ms
43,360 KB
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 # 

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;
        }
    }
}
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