結果

問題 No.284 門松と魔法(2)
コンテスト
ユーザー 紙ぺーぱー
提出日時 2015-07-12 21:48:19
言語 C#(csc)
(csc 3.9.0)
結果
AC  
実行時間 2,089 ms / 5,000 ms
コード長 12,917 bytes
コンパイル時間 2,091 ms
コンパイル使用メモリ 112,640 KB
実行使用メモリ 39,680 KB
最終ジャッジ日時 2024-07-08 06:07:00
合計ジャッジ時間 17,394 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge3
このコードへのチャレンジ
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ファイルパターン 結果
other AC * 40
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.Linq;
using System.Diagnostics;
using System.Collections.Generic;
using Debug = System.Diagnostics.Debug;
using StringBuilder = System.Text.StringBuilder;
using System.Numerics;

namespace Program
{

    public class Solver
    {
        /// <summary>
        /// O(NlogN)
        /// </summary>
        public void Solve()
        {
            var n = sc.Integer();
            var a = sc.Integer(n);
            var S = a.Distinct().ToList();
            S.Add(-1); S.Add(int.MaxValue);//番兵
            S.Sort();
            for (int i = 0; i < n; i++)
                a[i] = S.BinarySearch(a[i]);//座圧
            var sz = S.Count;
            var inc = new SegTree.SegmentTree(sz);//右端にの２つの竹について単調増加な最長門松部分列
            var dec = new SegTree.SegmentTree(sz);//右端の2つの竹について単調減少な最長門松部分列
            inc.Update(sz - 1, 0, 0);
            dec.Update(0, 0, sz - 1);
            foreach (var i in a)
            {
                //下がる
                {
                    var max = inc.Query(i + 1, sz, i);//prevがi以外であってnowがiより大きいもの
                    var pos = max.J;
                    var sec = Triplet.Max(inc.Query(i + 1, pos, i), inc.Query(pos + 1, sz, i));//pos以外から来て，prevがi以外であってnowがiより大きいもの
                    dec.Update(i, max.I + 1, max.J);//dp[pos1,i]=dp[prev1,pos1]+1
                    dec.Update(i, sec.I + 1, sec.J);//dp[pos2,i]=dp[prev2,pos2]+1
                }
                //上がる
                {
                    var max = dec.Query(0, i, i);//prevがi以外であってnowがiより小さいもの
                    var pos = max.J;
                    var sec = Triplet.Max(dec.Query(0, pos, i), dec.Query(pos + 1, i, i));//pos以外から来て，prevがi以外であってnowがiより大きいもの
                    inc.Update(i, max.I + 1, max.J);//dp[pos1,i]=dp[prev1,pos1]+1
                    inc.Update(i, sec.I + 1, sec.J);//dp[pos2,i]=dp[prev2,pos2]+1
                }
            }
            var ans = Math.Max(inc.Query(0, sz, -1).I, dec.Query(0, sz, -1).I);
            if (ans < 3) ans = 0;
            IO.Printer.Out.WriteLine(ans);
        }

        public IO.StreamScanner sc = new IO.StreamScanner(Console.OpenStandardInput());
        static T[] Enumerate<T>(int n, Func<int, T> f) { var a = new T[n]; for (int i = 0; i < n; ++i) a[i] = f(i); return a; }
        static public void Swap<T>(ref T a, ref T b) { var tmp = a; a = b; b = tmp; }
    }
}

#region main
static class Ex
{
    static public string AsString(this IEnumerable<char> ie) { return new string(System.Linq.Enumerable.ToArray(ie)); }
    static public string AsJoinedString<T>(this IEnumerable<T> ie, string st = " ") { return string.Join(st, ie); }
    static public void Main()
    {
        var solver = new Program.Solver();
        solver.Solve();
        Program.IO.Printer.Out.Flush();
    }
}
#endregion
#region Ex
namespace Program.IO
{
    using System.IO;
    using System.Text;
    using System.Globalization;
    public class Printer : StreamWriter
    {
        static Printer() { Out = new Printer(Console.OpenStandardOutput()) { AutoFlush = false }; }
        public static Printer Out { get; set; }
        public override IFormatProvider FormatProvider { get { return CultureInfo.InvariantCulture; } }
        public Printer(System.IO.Stream stream) : base(stream, new UTF8Encoding(false, true)) { }
        public Printer(System.IO.Stream stream, Encoding encoding) : base(stream, encoding) { }
        public void Write<T>(string format, T[] source) { base.Write(format, source.OfType<object>().ToArray()); }
        public void WriteLine<T>(string format, T[] source) { base.WriteLine(format, source.OfType<object>().ToArray()); }
    }
    public class StreamScanner
    {
        public StreamScanner(Stream stream) { str = stream; }
        public readonly Stream str;
        private readonly byte[] buf = new byte[1024];
        private int len, ptr;
        public bool isEof = false;
        public bool IsEndOfStream { get { return isEof; } }
        private byte read()
        {
            if (isEof) return 0;
            if (ptr >= len) { ptr = 0; if ((len = str.Read(buf, 0, 1024)) <= 0) { isEof = true; return 0; } }
            return buf[ptr++];
        }
        public char Char() { byte b = 0; do b = read(); while ((b < 33 || 126 < b) && !isEof); return (char)b; }

        public string Scan()
        {
            var sb = new StringBuilder();
            for (var b = Char(); b >= 33 && b <= 126; b = (char)read())
                sb.Append(b);
            return sb.ToString();
        }
        public string ScanLine()
        {
            var sb = new StringBuilder();
            for (var b = Char(); b != '\n'; b = (char)read())
                if (b == 0) break;
                else if (b != '\r') sb.Append(b);
            return sb.ToString();
        }
        public long Long()
        {
            if (isEof) return long.MinValue;
            long ret = 0; byte b = 0; var ng = false;
            do b = read();
            while (b != '-' && (b < '0' || '9' < b));
            if (b == '-') { ng = true; b = read(); }
            for (; true; b = read())
            {
                if (b < '0' || '9' < b)
                    return ng ? -ret : ret;
                else ret = ret * 10 + b - '0';
            }
        }
        public int Integer() { return (isEof) ? int.MinValue : (int)Long(); }
        public double Double() { return double.Parse(Scan(), CultureInfo.InvariantCulture); }
        private T[] enumerate<T>(int n, Func<T> f)
        {
            var a = new T[n];
            for (int i = 0; i < n; ++i) a[i] = f();
            return a;
        }

        public char[] Char(int n) { return enumerate(n, Char); }
        public string[] Scan(int n) { return enumerate(n, Scan); }
        public double[] Double(int n) { return enumerate(n, Double); }
        public int[] Integer(int n) { return enumerate(n, Integer); }
        public long[] Long(int n) { return enumerate(n, Long); }
    }
}
#endregion

namespace SegTree
{
    using K = Triplet<int, int, int>;
    #region SegTree
    [System.Diagnostics.DebuggerDisplay("Data={ToString()}")]
    public class SegmentTree
    {
        static public void Swap<T>(ref T a, ref T b) { var tmp = a; a = b; b = tmp; }
        readonly K min = new K(-1000000000, -1, -1);
        readonly Pair<K, K> MIN;
        int n;
        Pair<K, K>[] data;//length,now,prevのtripletのペア，
        public SegmentTree(int size)
        {
            MIN = new Pair<K, K>(min, min);
            n = 1;
            while (n < size)
                n <<= 1;
            data = new Pair<K, K>[n << 1];
            for (int i = 0; i < n << 1; i++)
                data[i] = MIN;

        }
        /// <summary>
        /// 葉ノードについて，fromが一致しないようにlengthを最大化
        /// </summary>
        void update(ref Pair<K, K> data, K t)
        {
            if (data.x.K == t.K)
            {
                if (data.x.I < t.I)
                    data.x = t;
            }
            else if (data.y.K == t.K)
            {
                if (data.y.I < t.I)
                    data.y = t;
                if (data.x.I < data.y.I)
                    Swap(ref data.x, ref data.y);
            }
            else
            {
                if (data.x.I < t.I)
                {
                    data.y = data.x;
                    data.x = t;
                }
                else if (data.y.I < t.I)
                    data.y = t;
            }
        }
        /// <summary>
        /// 節ノードについて，fromが一致しないようにlengthを最大化
        /// </summary>
        Pair<K, K> merge(Pair<K, K> l, Pair<K, K> r)
        {
            var a = new K[4] { l.x, l.y, r.x, r.y };
            Array.Sort(a);
            var x = a[3];
            for (int i = 2; i >= 0; i--)
                if (a[i].K == -1 || a[i].K != x.K) return new Pair<K, K>(x, a[i]);
            throw new Exception();

        }
        /// <summary>
        /// k番目の葉ノードにfromからきたときに長さv
        /// </summary>
        public void Update(int k, int v, int from)
        {
            var t = new K(v, k, from);
            k += n;
            update(ref data[k], t);
            k >>= 1;
            while (k > 0)
            {
                data[k] = merge(data[k << 1], data[(k << 1) + 1]);
                k >>= 1;
            }

        }
        /// <summary>
        /// [a,b)のfromがnowでないようなlengthの最大値を求める．
        /// </summary>
        public K Query(int a, int b, int now) { return Query(a, b, now, 1, 0, n); }
        private K Query(int a, int b, int now, int k, int l, int r)
        {
            if (r <= a || b <= l)
                return min;
            if (a <= l && r <= b)
            {
                if (data[k].x.K != now)
                    return data[k].x;
                else return data[k].y;
            }
            else
            {
                var vl = Query(a, b, now, k << 1, l, (l + r) >> 1);
                var vr = Query(a, b, now, (k << 1) + 1, (l + r) >> 1, r);
                return Triplet.Max(vl, vr);
            }
        }

        /*
        ///<summary>Data[i]</summary>>
        public long this[int i] { get { return data[i + n]; } }
        ///<summary>Minimum[a,b)</summary>>
        public long this[int l, int r] { get { return Query(l, r, 1, 0, n); } }
        public override string ToString()
        {
            return string.Join(",", Enumerable.Range(0, n).Select(i => this[i]).Where(v => v != Max));
        }
        public string Visualize()
        {
            var sb = new System.Text.StringBuilder();
            var k = 2;
            var len = n << 1;
            for (int i = 1; i < len; i++)
            {
                if (data[i] != Max) sb.Append(data[i]);
                else sb.Append('-');
                if (i < k - 1) sb.Append(',');
                else if (i < len - 1)
                {
                    sb.AppendLine();
                    k <<= 1;
                }
            }
            return sb.ToString();
        }
         //*/
    }
    #endregion
}
#region Triplet<ST,FT,TT>
static public class Triplet
{
    static public Triplet<FT, ST, TT> Create<FT, ST, TT>(FT f, ST s, TT t)
        where FT : IComparable<FT>
        where ST : IComparable<ST>
        where TT : IComparable<TT>
    { return new Triplet<FT, ST, TT>(f, s, t); }
    static public Triplet<FT, ST, TT> Min<FT, ST, TT>(Triplet<FT, ST, TT> p, Triplet<FT, ST, TT> q)
        where FT : IComparable<FT>
        where ST : IComparable<ST>
        where TT : IComparable<TT>
    { return (p.CompareTo(q) <= 0) ? p : q; }
    static public Triplet<FT, ST, TT> Max<FT, ST, TT>(Triplet<FT, ST, TT> p, Triplet<FT, ST, TT> q)
        where FT : IComparable<FT>
        where ST : IComparable<ST>
        where TT : IComparable<TT>
    { return (p.CompareTo(q) >= 0) ? p : q; }
}
public struct Triplet<FT, ST, TT> : IComparable<Triplet<FT, ST, TT>>
    where FT : IComparable<FT>
    where ST : IComparable<ST>
    where TT : IComparable<TT>
{
    public FT I;
    public ST J;
    public TT K;
    public Triplet(FT i, ST j, TT k) : this() { I = i; J = j; K = k; }
    public int CompareTo(Triplet<FT, ST, TT> other)
    {
        var cmp = I.CompareTo(other.I);
        if (cmp != 0) return cmp;
        cmp = J.CompareTo(other.J);
        if (cmp != 0) return cmp;
        return K.CompareTo(other.K);
    }
    public override string ToString() { return string.Format("{0} {1} {2}", I, J, K); }
}
#endregion
#region Compair
static public class Pair
{
    static public Pair<FT, ST> Create<FT, ST>(FT f, ST s)
        where FT : IComparable<FT>
        where ST : IComparable<ST>
    { return new Pair<FT, ST>(f, s); }
    static public Pair<FT, ST> Min<FT, ST>(Pair<FT, ST> p, Pair<FT, ST> q)
        where FT : IComparable<FT>
        where ST : IComparable<ST>
    { return (p.CompareTo(q) <= 0) ? p : q; }
    static public Pair<FT, ST> Max<FT, ST>(Pair<FT, ST> p, Pair<FT, ST> q)
        where FT : IComparable<FT>
        where ST : IComparable<ST>
    { return (p.CompareTo(q) >= 0) ? p : q; }
}
public struct Pair<FT, ST> : IComparable<Pair<FT, ST>>
    where FT : IComparable<FT>
    where ST : IComparable<ST>
{
    public FT x;
    public ST y;
    public Pair(FT f, ST s) : this() { x = f; y = s; }

    public int CompareTo(Pair<FT, ST> other)
    {
        var cmp = x.CompareTo(other.x);
        return cmp != 0 ? cmp : y.CompareTo(other.y);
    }
    public override string ToString() { return string.Format("{0} {1}", x, y); }
}
#endregion
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