結果

問題 No.1188 レベルX門松列
コンテスト
ユーザー りあん
提出日時 2020-08-22 15:18:57
言語 C#(csc)
(csc 3.9.0)
結果
AC  
実行時間 396 ms / 2,000 ms
コード長 8,476 bytes
コンパイル時間 1,156 ms
コンパイル使用メモリ 125,048 KB
実行使用メモリ 48,444 KB
最終ジャッジ日時 2024-10-15 09:34:25
合計ジャッジ時間 6,397 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge2
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
sample AC * 3
other AC * 21
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.Generic;
using System.Linq;
using System.IO;
using System.Threading;
using System.Text;
using System.Text.RegularExpressions;
using System.Diagnostics;
using static util;
using P = pair<int, int>;

class Program {
    static void Main(string[] args) {
        var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
        var solver = new Solver(sw);
        // var t = new Thread(solver.solve, 1 << 28); // 256 MB
        // t.Start();
        // t.Join();
        solver.solve();
        sw.Flush();
    }
}

class Solver {
    StreamWriter sw;
    Scan sc;
    void Prt(string a) => sw.WriteLine(a);
    void Prt<T>(IEnumerable<T> a) => Prt(string.Join(" ", a));
    void Prt(params object[] a) => Prt(string.Join(" ", a));
    public Solver(StreamWriter sw) {
        this.sw = sw;
        this.sc = new Scan();
    }

    public void solve() {
        int n = sc.Int;
        var a = sc.IntArr;
        var cmp = a.compress();
        a = a.Select(x => cmp[x]).ToArray();
        var l1 = new int[n];
        var l2 = new int[n];
        {
            var sg1 = new Segtree<int>(n, Math.Max, 0);
            var sg2 = new Segtree<int>(n, Math.Max, 0);
            for (int i = 0; i < n; i++)
            {
                l1[i] = sg1.run(0, a[i]) + 1;
                l2[i] = sg2.run(a[i] + 1, n) + 1;
                sg1.update(a[i], l1[i]);
                sg2.update(a[i], l2[i]);
            }
        }
        var r1 = new int[n];
        var r2 = new int[n];
        {
            var sg1 = new Segtree<int>(n, Math.Max, 0);
            var sg2 = new Segtree<int>(n, Math.Max, 0);
            for (int i = n - 1; i >= 0 ; i--)
            {
                r1[i] = sg1.run(0, a[i]) + 1;
                r2[i] = sg2.run(a[i] + 1, n) + 1;
                sg1.update(a[i], r1[i]);
                sg2.update(a[i], r2[i]);
            }
        }
        int ans = 0;
        for (int i = 0; i < n; i++)
        {
            ans = Math.Max(ans, Math.Max(Math.Min(l1[i], r1[i]), Math.Min(l2[i], r2[i])) - 1);
        }
        Prt(ans);
    }
}

class pair<T, U> : IComparable<pair<T, U>> {
    public T v1;
    public U v2;
    public pair() : this(default(T), default(U)) {}
    public pair(T v1, U v2) { this.v1 = v1; this.v2 = v2; }
    public int CompareTo(pair<T, U> a) {
        int c = Comparer<T>.Default.Compare(v1, a.v1);
        return c != 0 ? c : Comparer<U>.Default.Compare(v2, a.v2);
    }
    public override string ToString() => v1 + " " + v2;
    public void Deconstruct(out T a, out U b) { a = v1; b = v2; }
}
static class util {
    // public static readonly int M = 1000000007;
    public static readonly int M = 998244353;
    public static readonly long LM = 1L << 60;
    public static readonly double eps = 1e-11;
    public static void DBG(string a) => Console.Error.WriteLine(a);
    public static void DBG<T>(IEnumerable<T> a) => DBG(string.Join(" ", a));
    public static void DBG(params object[] a) => DBG(string.Join(" ", a));
    public static void Assert(params bool[] conds) {
        if (conds.Any(x => !x)) throw new Exception();
    }
    public static pair<T, U> make_pair<T, U>(T v1, U v2) => new pair<T, U>(v1, v2);
    public static int CompareList<T>(IList<T> a, IList<T> b) where T : IComparable<T> {
        for (int i = 0; i < a.Count && i < b.Count; i++)
            if (a[i].CompareTo(b[i]) != 0) return a[i].CompareTo(b[i]);
        return a.Count.CompareTo(b.Count);
    }
    public static bool inside(int i, int j, int h, int w) => i >= 0 && i < h && j >= 0 && j < w;
    public static readonly int[] dd = { 0, 1, 0, -1 };
    // static readonly string dstring = "RDLU";
    public static IEnumerable<P> adjacents(int i, int j)
        => Enumerable.Range(0, dd.Length).Select(k => new P(i + dd[k], j + dd[k ^ 1]));
    public static IEnumerable<P> adjacents(int i, int j, int h, int w)
        => adjacents(i, j).Where(p => inside(p.v1, p.v2, h, w));
    public static IEnumerable<P> adjacents(this P p) => adjacents(p.v1, p.v2);
    public static IEnumerable<P> adjacents(this P p, int h, int w) => adjacents(p.v1, p.v2, h, w);
    public static IEnumerable<int> all_subset(this int p) {
        for (int i = 0; ; i = i - p & p) {
            yield return i;
            if (i == p) break;
        }
    }
    public static Dictionary<T, int> compress<T>(this IEnumerable<T> a)
        => a.Distinct().OrderBy(v => v).Select((v, i) => new { v, i }).ToDictionary(p => p.v, p => p.i);
    public static Dictionary<T, int> compress<T>(params IEnumerable<T>[] a) => compress(a.SelectMany(x => x));
    public static T[] inv<T>(this Dictionary<T, int> dic) {
        var res = new T[dic.Count];
        foreach (var item in dic) res[item.Value] = item.Key;
        return res;
    }
    public static void swap<T>(ref T a, ref T b) where T : struct { var t = a; a = b; b = t; }
    public static void swap<T>(this IList<T> a, int i, int j) where T : struct { var t = a[i]; a[i] = a[j]; a[j] = t; }
    public static T[] copy<T>(this IList<T> a) {
        var ret = new T[a.Count];
        for (int i = 0; i < a.Count; i++) ret[i] = a[i];
        return ret;
    }
}

class Scan {
    StreamReader sr;
    public Scan() { sr = new StreamReader(Console.OpenStandardInput()); }
    public Scan(string path) { sr = new StreamReader(path); }
    public int Int => int.Parse(Str);
    public long Long => long.Parse(Str);
    public double Double => double.Parse(Str);
    public string Str => ReadLine.Trim();
    public string ReadLine => sr.ReadLine();
    public pair<T, U> Pair<T, U>() {
        T a; U b;
        Multi(out a, out b);
        return new pair<T, U>(a, b);
    }
    public P P => Pair<int, int>();
    public int[] IntArr => StrArr.Select(int.Parse).ToArray();
    public long[] LongArr => StrArr.Select(long.Parse).ToArray();
    public double[] DoubleArr => StrArr.Select(double.Parse).ToArray();
    public string[] StrArr => Str.Split(new[]{' '}, StringSplitOptions.RemoveEmptyEntries);
    bool eq<T, U>() => typeof(T).Equals(typeof(U));
    T ct<T, U>(U a) => (T)Convert.ChangeType(a, typeof(T));
    T cv<T>(string s) => eq<T, int>()    ? ct<T, int>(int.Parse(s))
                       : eq<T, long>()   ? ct<T, long>(long.Parse(s))
                       : eq<T, double>() ? ct<T, double>(double.Parse(s))
                       : eq<T, char>()   ? ct<T, char>(s[0])
                                         : ct<T, string>(s);
    public void Multi<T>(out T a) => a = cv<T>(Str);
    public void Multi<T, U>(out T a, out U b) {
        var ar = StrArr; a = cv<T>(ar[0]); b = cv<U>(ar[1]);
    }
    public void Multi<T, U, V>(out T a, out U b, out V c) {
        var ar = StrArr; a = cv<T>(ar[0]); b = cv<U>(ar[1]); c = cv<V>(ar[2]);
    }
    public void Multi<T, U, V, W>(out T a, out U b, out V c, out W d) {
        var ar = StrArr; a = cv<T>(ar[0]); b = cv<U>(ar[1]); c = cv<V>(ar[2]); d = cv<W>(ar[3]);
    }
    public void Multi<T, U, V, W, X>(out T a, out U b, out V c, out W d, out X e) {
        var ar = StrArr; a = cv<T>(ar[0]); b = cv<U>(ar[1]); c = cv<V>(ar[2]); d = cv<W>(ar[3]); e = cv<X>(ar[4]);
    }
}

class Segtree<T> {
    int n;
    T[] data;
    Func<T, T, T> f;
    T identity;

    public Segtree(int m, Func<T, T, T> f, T identity) {
        this.f = f;
        this.identity = identity;
        n = 1;
        while (n < m) n <<= 1;
        data = new T[(n << 1) - 1];
        for (int i = 0; i < data.Length; i++) data[i] = identity;
    }
    public Segtree(int m, IList<T> ini, Func<T, T, T> f, T identity) : this(m, f, identity) {
        for (int i = 0; i < m; ++i) assign(i, ini[i]);
        all_update();
    }
    public void assign(int j, T x) => data[j + n - 1] = x;
    public void update(int j, T x) {
        assign(j, x);
        update(j);
    }
    public void update(int j) {
        int i = j + n - 1;
        while (i > 0) {
            i = i - 1 >> 1;
            data[i] = f(data[i << 1 | 1], data[i + 1 << 1]);
        }
    }
    public void all_update() {
        for (int i = n - 2; i >= 0; i--)
            data[i] = f(data[i << 1 | 1], data[i + 1 << 1]);
    }
    public T at(int i) => data[i + n - 1];

    // [s, t)
    public T run(int s, int t) => run(s, t, 0, 0, n);
    T run(int s, int t, int k, int l, int r) => r <= s || t <= l ? identity : s <= l && r <= t ? data[k]
            : f(run(s, t, k << 1 | 1, l, l + r >> 1), run(s, t, k + 1 << 1, l + r >> 1, r));
}
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