ABC393-E GCD of Subset

問題へのリンク

C#のソース

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

class Program
{
    static string InputPattern = "InputX";

    static List<string> GetInputList()
    {
        var WillReturn = new List<string>();

        if (InputPattern == "Input1") {
            WillReturn.Add("5 2");
            WillReturn.Add("3 4 6 7 12");
            //3
            //4
            //6
            //1
            //6
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("3 3");
            WillReturn.Add("6 10 15");
            //1
            //1
            //1
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("10 3");
            WillReturn.Add("414003 854320 485570 52740 833292 625990 909680 885153 435420 221663");
            //59
            //590
            //590
            //879
            //879
            //590
            //20
            //879
            //590
            //59
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static void Main()
    {
        List<string> InputList = GetInputList();
        long[] wkArr = InputList[0].Split(' ').Select(pX => long.Parse(pX)).ToArray();
        long K = wkArr[1];

        long[] AArr = InputList[1].Split(' ').Select(pX => long.Parse(pX)).ToArray();
        long MaxA = AArr.Max();

        // 個数[数]なDict
        var CntDict = new Dictionary<long, long>();
        foreach (long EachA in AArr) {
            if (CntDict.ContainsKey(EachA) == false) {
                CntDict[EachA] = 0;
            }
            CntDict[EachA]++;
        }

        // 答え[数]なDict
        var AnswerDict = new Dictionary<long, long>();
        foreach (long EachA in AArr) {
            AnswerDict[EachA] = 1;
        }

        for (long I = 2; I <= MaxA; I++) {
            var TargetList = new List<long>();
            long AppearCnt = 0;
            foreach (long EachBaisuu in DeriveBaisuuEnum(I, MaxA)) {
                if (CntDict.ContainsKey(EachBaisuu)) {
                    TargetList.Add(EachBaisuu);
                    AppearCnt += CntDict[EachBaisuu];
                }
            }
            if (AppearCnt >= K) {
                TargetList.ForEach(pX => AnswerDict[pX] = I);
            }
        }

        var sb = new System.Text.StringBuilder();
        foreach (long EachA in AArr) {
            sb.Append(AnswerDict[EachA]);
            sb.AppendLine();
        }
        Console.Write(sb.ToString());
    }

    // 値と上限を引数として、倍数を列挙する
    static IEnumerable<long> DeriveBaisuuEnum(long pVal, long pLimit)
    {
        for (long I = pVal; I <= pLimit; I += pVal) {
            yield return I;
        }
    }
}

解説

重複値の対応で、度数分布表を求めてから、
調査級数の計算量で解いてます。