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@anonymously115

paizaラーニングレベルアップ問題集の「配列活用メニュー」をLINQでやってみた。

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paizaラーニングレベルアップ問題集の配列活用メニューを、LINQ（Language-Integrated Query）を使ってやってみました。

指定の要素のカウント

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int[] NK = Console.ReadLine().Split().Select(int.Parse).ToArray();
		var (N, K) = (NK[0], NK[1]);
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		System.Console.WriteLine(A.Count(a => a == K));
	}
}
全ての要素の和

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int N = int.Parse(Console.ReadLine());
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		System.Console.WriteLine(A.Sum());
	}
}
配列の最大値

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int N = int.Parse(Console.ReadLine());
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		System.Console.WriteLine(A.Max());
	}
}
配列の最小値

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int N = int.Parse(Console.ReadLine());
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		System.Console.WriteLine(A.Min());
	}
}
指定要素があるかの判定

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int[] NK = Console.ReadLine().Split().Select(int.Parse).ToArray();
		var (N, K) = (NK[0], NK[1]);
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		System.Console.WriteLine(A.Any(a => a == K) ? "Yes" : "No");
	}
}
指定要素の先頭位置

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int[] NK = Console.ReadLine().Split().Select(int.Parse).ToArray();
		var (N, K) = (NK[0], NK[1]);
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		int index = A
			.Select((a, i) => new { Id = i + 1, Value = a })
			.Where(a => a.Value == K)
			.Select(a => a.Id)
			.FirstOrDefault();
		if (index == 0) Console.WriteLine(-1);
		else Console.WriteLine(index);
	}
}
要素の種類数

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int N = int.Parse(Console.ReadLine());
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		Console.WriteLine(A.Distinct().Count());
	}
}
全ての要素に対する操作

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int[] NK = Console.ReadLine().Split().Select(int.Parse).ToArray();
		var (N, K) = (NK[0], NK[1]);
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		int[] B = A.Select(a => a + K).ToArray();
		foreach (int b in B) Console.WriteLine(b);
	}
}
配列の順序の反転

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int N = int.Parse(Console.ReadLine());
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		int[] B = A.Reverse().ToArray();
		foreach (int b in B) Console.WriteLine(b);
	}
}
変数の入れ替え

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int[] XY = Console.ReadLine().Split().Select(int.Parse).ToArray();
		var (X, Y) = (XY[0], XY[1]);
		(X, Y) = (Y, X);
		Console.WriteLine($"{X} {Y}");
	}
}
指定要素の入れ替え

using System;
using System.Linq;

public class Program
{
	static void Swap<T>(ref T a, ref T b)
	{
		(a, b) = (b, a);
	}

	public static void Main()
	{
		int N = int.Parse(Console.ReadLine());
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		int[] XY = Console.ReadLine().Split().Select(int.Parse).ToArray();
		var (X, Y) = (XY[0] - 1, XY[1] - 1);
		Swap(ref A[X], ref A[Y]);
		foreach (int a in A) Console.WriteLine(a);
	}
}
末尾への要素の追加
using System;
using System.Linq;
using System.Collections.Generic;

public class Program
{
	public static void Main()
	{
		int N = int.Parse(Console.ReadLine());
		List<int> A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToList();
		int b = int.Parse(Console.ReadLine());
		A.Add(b);
		foreach (int a in A) Console.WriteLine(a);
	}
}
指定位置への要素の追加

using System;
using System.Linq;
using System.Collections.Generic;

public class Program
{
	public static void Main()
	{
		int N = int.Parse(Console.ReadLine());
		List<int> A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToList();
		int[] nb = Console.ReadLine().Split().Select(int.Parse).ToArray();
		var (n, b) = (nb[0], nb[1]);
		A.Insert(n, b);
		foreach (int a in A) Console.WriteLine(a);
	}
}
指定要素の削除

using System;
using System.Linq;
using System.Collections.Generic;

public class Program
{
	public static void Main()
	{
		int N = int.Parse(Console.ReadLine());
		List<int> A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToList();
		int n = int.Parse(Console.ReadLine()) - 1;
		A.RemoveAt(n);
		foreach (int a in A) Console.WriteLine(a);
	}
}
九九表

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int[][] A = Enumerable.Range(1, 9).Select(i => Enumerable.Range(1, 9).Select(j => i * j).ToArray()).ToArray();
		foreach (int[] a in A) Console.WriteLine(String.Join(" ", a));
	}
}
全ての要素を用いた処理

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int N = int.Parse(Console.ReadLine());
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		for (int i = 0; i < N; i++)
		{
			for (int j = 0; j < i; j++)
			{
				Console.WriteLine(A[i] * A[j]);
			}
		}
	}
}
配列のサイズの変更

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int[] Nn = Console.ReadLine().Split().Select(int.Parse).ToArray();
		var (N, n) = (Nn[0], Nn[1]);
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		Array.Resize(ref A, n);
		foreach (int a in A) Console.WriteLine(a);
	}
}
重複要素の削除

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int N = int.Parse(Console.ReadLine());
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		int[] B = A.Distinct().ToArray();
		foreach (int b in B) Console.WriteLine(b);
	}
}
条件を満たす要素のみの配列作成

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int[] NK = Console.ReadLine().Split().Select(int.Parse).ToArray();
		var (N, K) = (NK[0], NK[1]);
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		int[] B = A.Where(a => a >= K).ToArray();
		foreach (int b in B) Console.WriteLine(b);
	}
}
傾斜配点

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int N = int.Parse(Console.ReadLine());
		int[] M = Console.ReadLine().Split().Select(int.Parse).ToArray();
		int[][] A = Enumerable.Range(0, N).Select(_ => Console.ReadLine().Split().Select(int.Parse).ToArray()).ToArray();
		Console.WriteLine(A.Select(a => a.Select((_, i) => M[i] * a[i]).Sum()).Max());
	}
}
内定

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int[] NKM = Console.ReadLine().Split().Select(int.Parse).ToArray();
		var (N, K, M) = (NKM[0], NKM[1], NKM[2]);
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		Console.WriteLine(A.OrderByDescending(a => a).Where((a, i) => i >= M && a >= K).Count());
	}
}
queue(9)係

using System;
using System.Linq;
using System.Collections.Generic;

public class Program
{
	public static void Main()
	{
		int N = int.Parse(Console.ReadLine());
		Queue<int> A = new Queue<int>();
		for (int i = 0; i < N; i++)
		{
			string[] s = Console.ReadLine().Split();
			if ("in".Equals(s[0]))
			{
				int n = int.Parse(s[1]);
				A.Enqueue(n);
			}
			else if ("out".Equals(s[0]))
			{
				if (A.Count > 0)
				{
					A.Dequeue();
				}
			}
		}
		while (A.Count > 0)
		{
			Console.WriteLine(A.Dequeue());
		}
	}
}
二人三脚

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int N = int.Parse(Console.ReadLine());
		int[] A = Enumerable.Range(0, N).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		int[] B = A.OrderBy(a => a).ToArray();
		int[] D = Enumerable.Range(1, N - 1).Select(i => B[i] - B[i - 1]).ToArray();
		int k = Array.IndexOf(D, D.Min());
		Console.WriteLine(B[k]);
		Console.WriteLine(B[k + 1]);
	}
}
場所取り

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int[] NKF = Console.ReadLine().Split().Select(int.Parse).ToArray();
		var (K, F) = (NKF[1], NKF[2]);
		int[] A = Enumerable.Range(0, K).Select(_ => int.Parse(Console.ReadLine())).ToArray();
		int[] B = A.Where((_, i) => i >= F).Distinct().ToArray();
		foreach (int b in B) Console.WriteLine(b);
	}
}
ボウリング

using System;
using System.Linq;

public class Program
{
	public static void Main()
	{
		int[] P = Console.ReadLine().Split().Select(int.Parse)
			.Concat(Console.ReadLine().Split().Select(int.Parse))
			.Concat(Console.ReadLine().Split().Select(int.Parse))
			.Concat(Console.ReadLine().Split().Select(int.Parse))
			.Reverse().ToArray();
		Console.WriteLine(Array.IndexOf(P, 1) + 1);
		Console.WriteLine(P.Count(p => p == 1));
	}
}
集団行動

using System;
using System.Linq;

public class Program
{
	static void Swap<T>(ref T a, ref T b)
	{
		(a, b) = (b, a);
	}

	public static void Main()
	{
		int[] NQ = Console.ReadLine().Split().Select(int.Parse).ToArray();
		var (N, Q) = (NQ[0], NQ[1]);
		int[] A = Enumerable.Range(1, N).ToArray();
		for (int q = 0; q < Q; q++)
		{
			string[] s = Console.ReadLine().Split();
			if ("swap".Equals(s[0]))
			{
				var (a, b) = (int.Parse(s[1]) - 1, int.Parse(s[2]) - 1);
				Swap(ref A[a], ref A[b]);
			}
			else if ("reverse".Equals(s[0]))
			{
				A = A.Reverse().ToArray();
			}
			else if ("resize".Equals(s[0]))
			{
				int c = int.Parse(s[1]);
				if (c < A.Length)
				{
					Array.Resize(ref A, c);
				}
			}
		}
		foreach (int a in A)
		{
			Console.WriteLine(a);
		}
	}
}
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