def mode(lst):
    freq = {x:lst.count(x) for x in set(lst)}
    if len(freq) == 1 or len(freq) == len(lst):
        return None
    else:
        return [x for x in freq.keys() if freq[x] == max(freq.values())]


for lst in [[12, 17, 19, 17, 23], [26, 37, 26, 37, 91], [28, 30, 32, 34, 144]]:
    print(lst, mode(lst))

import collections
def cb(list):
    o = collections.Counter(list).most_common()
    max,m = o[0][1],[]
    for num in o:
        if num[1] == max:m.append(num[0])
    if len(m)==len(list):return '없음'
    return m
print(cb([1,2,3,4,5,5]))
print(cb([1,2,3,4,4,5,5]))
print(cb([1,2,3,4,5]))

def mode(n):
    Max = 0
    for x in list(set(n)):
        if n.count(x) > Max:
            Max = n.count(x)
    print(Max if Max <= 1 else 'None')

def mode(v):
    tmp = set(v)
    if len(tmp) in (1, len(v)): return None
    cnt = {}
    for i in tmp:
        getcnt = v.count(i)
        try   : cnt[getcnt].append(i)
        except: cnt[getcnt] = [i]
    return cnt[max(cnt)]

public class Main {

    public static void print(int a[])
    {
        int check[] =new int[a.length];
        for(int i=0;i<a.length;i++)
        {
            check[i]=0;

        }
        int maxidx=0;
        for(int i=0; i<a.length ;i++)
        {

            for(int j=i+1;j<a.length;j++)
            {
                if( a[i] == a[j])
                {
                    check[i]++;

                    if(check[maxidx]<check[i])
                    {
                        maxidx=i;
                    }
                }
            }
        }
        if(check[maxidx] ==0)
        {
            System.out.println("없다.");
            return;
        }
        for(int i=0;i<check.length;i++)
        {
            if(check[maxidx]==check[i])
            {
                System.out.printf("%d ",a[i]);
            }

        }
        System.out.printf("\n");

    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        int arr[] = {12, 17, 19, 17, 23};
        int arr2[]={26, 37, 26, 37, 91};
        int arr3[]={28, 30, 32, 34, 144};
        print(arr);
        print(arr2);
        print(arr3);


    }

}

C# Linq

class Program
{
    static void Main(string[] args)
    {
        int[] ary1 = { 12, 17, 19, 17, 23, 23 }; // 17
        int[] ary2 = { 26, 37, 26, 37, 91 }; // 26, 37
        int[] ary3 = { 28, 30, 32, 34, 144 }; // 없다

        int[] ary = ary3;

        var hash = new HashSet<int>(ary);

        //모두 다른 값 or 동일한 값인 경우 체크
        if (hash.Count == ary.Length || hash.Count == 1)
        {
            Console.WriteLine("최빈 값이 없습니다.");
            return;
        }

        var cntLists =  from x in hash
                        join y in ary on x equals y
                        group x by x into gp
                        select new
                        {
                            Key = gp.Key,
                            Count = gp.Count()
                        };

        int max = cntLists.Max(x => x.Count);

        var resultList = from x in cntLists
                         where x.Count == max
                         select x;

        foreach (var v in resultList)
        {
            Console.WriteLine($"{v.Key}: {v.Count}개" );
        }
    }
}

list1 = [[12, 17, 19, 17, 23],
    [26, 37, 26, 37, 91],
    [28, 30, 32, 34, 144]]

def mode(l1):
    a1 = {x:l1.count(x) for x in set(l1)}
    a2 = [a for a in a1.keys() if a1[a] == max(a1.values())]
    return "없다" if len(a1) == len(a2) else a2


for l1 in list1:
    print(l1, "=", mode(l1))

출력

[12, 17, 19, 17, 23] = [17]
[26, 37, 26, 37, 91] = [26, 37]
[28, 30, 32, 34, 144] = 없다

const arr = [12, 12, 12, 11];

const getMode = (arr) => {
  let mostFrequentCnt = 1;
  const mode = [];
  const _map = new Map();

  for (const item of arr) {
    const hasValue = _map.get(item);
    const cnt = hasValue === undefined ? 1: hasValue + 1;
    _map.set(item, cnt);
  }

  for (const [key, value] of _map) {
    if (value > mostFrequentCnt) {
      mostFrequentCnt = value;
    }
  }

  if (mostFrequentCnt === 1) return null;
  for (const [key, value] of _map) {
    if (value === mostFrequentCnt) {
      mode.push(key);
    }
  }
  if (mostFrequentCnt === arr.length) return null;
  return mode;
};


if (getMode(arr)) {
  console.log('최빈값:', getMode(arr).join(','));
} else {
  console.log('없다');
}

import java.util.Arrays;

public class TEST07 {

    public static void main(String[] args) {
        int[] data1 = {12, 17, 19, 17, 23,23};
        int[] data2 = {26, 37, 26, 37, 91};
        int[] data3 = {28, 30, 32, 34, 144};

        int[] max = maxShow(data1);
        for (int i = 0; i < max.length; i++) {
            if (max[i] != 0) {
                System.out.print(max[i] + " ");             
            }
        }
        System.out.println(" ");
        max = maxShow(data2);
        for (int i = 0; i < max.length; i++) {
            if (max[i] != 0) {
                System.out.print(max[i] + " ");             
            }
        }
        System.out.println(" ");
        max = maxShow(data3);
        for (int i = 0; i < max.length; i++) {
            if (max[i] != 0) {
                System.out.print(max[i] + " ");             
            }
        }

    }

    public static int[] maxShow(int[] data) {
        Arrays.sort(data);
        int[] value = new int[data.length];
        int[] showCnt = new int[data.length];

        int[] max = new int[data.length];
        int cnt = 1;
        int init = data[0];
        int idx = 0;
        for (int i = 1; i < data.length; i++) {

            if (init == data[i]) {
                cnt = cnt + 1;
            }
            else {
                value[idx] = init;
                showCnt[idx++] = cnt;
                init = data[i];
                cnt = 1;
            }
            if (i == (data.length - 1)) {
                value[idx] = init;
                showCnt[idx] = cnt;
            }

        }

        idx = 0;
        int max_value = searchMax(showCnt);
        if (max_value == 1) {
            return max;
        }
        for (int i = 0; i < showCnt.length; i++) {
            if (max_value == showCnt[i]) {
                max[idx++] = value[i];
            }
        }

        return max;
    }

    public static int searchMax(int[] data) {
        int max = 0;
        for (int i = 0; i < data.length; i++) {
            if (data[i] > max) {
                max = data[i];
            }
        }

        return max;
    }
}

Ruby

def most_freq(arr)
  hash = arr.reduce(Hash.new(0)) {|h,freq| h[freq] += 1; h}
  mfreq = hash.select {|_,freq| freq == hash.values.max }
  mfreq.rassoc(1) ? "not exist" : mfreq.one? ? mfreq.keys[0] : mfreq.map(&:first)
end

Test

expect( most_freq([12, 17, 19, 17, 23]) ).to eq 17
expect( most_freq([26, 37, 26, 37, 91]) ).to eq [26, 37]
expect( most_freq([28, 30, 32, 34, 144]) ).to eq "not exist"

from collections import Counter

def most_common(xs):
  c = Counter(xs)
  return [x for x, y in c.items() if y == c.most_common()[0][1]]

def freq(lista):
    freqdic = {}
    for i in lista:
        total = 0
        for j in lista:
            if(i==j):
                total += 1
        freqdic[i] = total
    return max(freqdic,key=freqdic.get)

clear
clc
%최빈값구하기(해당 함수 미사용)
n=input('벡터 입력:');
sortn=sort(n);%정렬
count=1;
c=1;
k=1;
for i=2:length(sortn)
    if sortn(i)~=sortn(i-1)
        if count>c
            c=count;
            freq=sortn(i-1);
            count=1;
        elseif count==c && count~=1
            c=count;
            freq(k)=freq;
            freq(k+1)=sortn(i-1);
            k=k+1;
            count=1;
        end
    else
        count=count+1;
    end
end
if c==1 || count==length(n)
    fprintf('최빈값은 없다\n');
elseif length(freq)>=2
    fprintf('최빈값:\n');
    disp(freq);    
else
    fprintf('최빈값: %d\n',freq);
end

def mode(lst):
    cnt = {n:lst.count(n) for n in lst}
    ret = [n for n in cnt.keys()
           if cnt[n] == max(cnt.values()) and cnt[n] > 1]
    return ret

for lst in [[12, 17, 19, 17, 23],
            [26, 37, 26, 37, 91],
            [28, 30, 32, 34, 144]]:
    print(lst, mode(lst), sep=':')

sample = list(map(int, input().split()))

count_result = []
temp = []
tempresult = []

for i in sample:
    count = 0
    for j in sample:
        if i == j:
            count += 1
    count_result.append(count)

compare = count_result[0]

for i in range(len(count_result) - 1):
    if compare < count_result[i + 1]:
        compare = count_result[i + 1]

for i in range(len(count_result)):
    if compare == 1:
        break
    elif compare == count_result[i]:
        tempresult.append(sample[i])

result = list(set(tempresult))
result.sort()

if result == []:
    print('없다')
else:
    print(result)

def max_freq(lst):
  if len(set(lst)) != len(lst):
    freq_dict = {}
    for num in lst:
      freq_dict[num] = 0
    for num in lst:
      freq_dict[num] += 1

    reverse_tuple = sorted([(j, i) for i, j in freq_dict.items()], key = lambda x: x[0], reverse=True)

    dup = 0
    for i in range(1, len(reverse_tuple)):
      if reverse_tuple[0][0] == reverse_tuple[i][0]:
        dup += 1

    freq_tuple = [reverse_tuple[i][1] for i in range(dup+1)]

    return freq_tuple

  else:
    return '최빈값이 없습니다.'

C#

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

namespace CD187
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            List<int> testCase;
            testCase = new List<int>() { 12, 17, 19, 17, 23 };
            Console.WriteLine(Mode(testCase));
            testCase = new List<int>() { 26, 37, 26, 37, 91 };
            Console.WriteLine(Mode(testCase));
            testCase = new List<int>() { 28, 30, 32, 34, 144 };
            Console.WriteLine(Mode(testCase));
        }

        private static string Mode(List<int> list)
        {
            // 딕셔너리 구성(key = 숫자, value = 리스트 내의 개수)
            var countDic = list.GroupBy(e => e).ToDictionary(g => g.Key, g => g.Count());
            // 딕셔너리 아이템의 중복 개수가 중복 개수의 최대값과 동일한 아이템 개수 계산
            int maxVal = countDic.Values.Max();
            int criteria = countDic.Where(g => g.Value == maxVal).Select(g => g.Key).Count();
            // 동일한 아이템 개수 == 리스트의 항목 개수인 경우(즉, 모두 같거나, 모두 다르거나) 최빈값 없음
            string result = criteria == list.Count() ? "없다" :
                // 그렇지 않은 경우 딕셔너리 키(리스트 항목)(들을) 반환
                string.Join(", ", countDic.Where(g => g.Value == maxVal).Select(g => g.Key));
            return result;
        }
    }
}

mylist = [40, 40, 26, 26, 4]

eval_list= [mylist.count(item) for item in mylist]
res = []
if max(eval_list) == 1:
    print("No mode exists")
else:
    for val in range(0,len(eval_list)):
        if eval_list[val] == max(eval_list):
            res.append(mylist[val])

for item in set(res):
    print(item, end = " ")

def freq(a):
    freqlist = []
    freqset = set([])
    result = {}
    result2 = []
    for i in a:
        freqlist.append(i)
        freqset.add(i)
    if len(freqset) == len(freqlist):
        return "없다"
    else:
        for j in freqlist:
            c = freqlist.count(j)
            result[j] = c
        for k , l in result.items():
            count = max(result.values())
            if l == count:
                result2.append(k)
    print(result2)

def mode(n): Max = 0 for x in list(set(n)): if n.count(x) > Max: Max = n.count(x) print(Max if Max <= 1 else 'None')

java 입력받는 숫자의 개수는 10개이고, 입력값이 10000을 넘지않는 가정하에 품

import java.util.*;

public class q4 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> array = new ArrayList<>();
        int[][] count = new int[10000][2];
        for (int i = 0; i < 10; i++) {
            array.add(sc.nextInt());
        }
        for (int i = 0; i < 10; i++) {
            count[array.get(0)][1]++;
            array.remove(0);
        }
        int max_count = 0;
        for (int i = 0; i < 10000; i++) {
            if (max_count < count[i][1]) {
                max_count = count[i][1];
            }
        }
        if (max_count == 1) {
            System.out.println("없다");
            System.exit(0);
        } else {
            for (int i = 0; i < 10000; i++) {
                if (count[i][1] == max_count) {
                    System.out.print(i + " ");
                }
            }
        }
    }
}

public class 최빈값구하기 {

    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);
        String str = scan.nextLine();
        ArrayList<Integer> list = new ArrayList<Integer>();
        ArrayList<Integer> list2 = new ArrayList<Integer>();
        String[] arr = str.split(", ");
        for(int i=0; i<5; i++) {
            list.add(Integer.parseInt(arr[i]));
        }

        int mode = 0;
        for(int i=0; i<list.size(); i++) {
            int count = 0;
            for(int j=0; j<list.size(); j++) {
                if(list.get(i)==list.get(j)) {
                    count++;
                }
            }
            if(count>=mode&&count>1) {
                mode = count;
                list2.add(list.get(i));
                list2.add(mode);
                for(int k=0; k<list.size(); k++) {
                    if(list.get(i)==list.get(k)&&i!=k) {
                        list.remove(k);
                        k--;
                    }
                }
            }
        }
        if(list2.size()>1) {
            int 빈도 = 0;
            for(int i=1; i<list2.size(); i=i+2) {
                if(list2.get(i)>=빈도) {
                    빈도=list2.get(i);
                }
            }
            for(int i=1; i<list2.size(); i++) {
                if(list2.get(i)==빈도) {
                    System.out.print(list2.get(i-1)+" ");
                }
            }
        }

        else if(list2.size()==0) {
            System.out.println("없다");
        }

    }

}

lst1=[26, 37, 26, 37, 91]
def mode(lst):
    frq={}
    nlst=[]
    for n in lst:
        frq[n]=frq.get(n,0)+1
    vlst=list(frq.values())
    if len(frq)==1 or len(lst)==len(frq) or len(set(vlst))==1: #최빈값이 없을 조건: 1. 모든 자료값이 같음, 2. 모든 자료값이 다름, 3.자료값의 도수가 전부 같을 경우
        return None
    else:
        for n in list(frq.keys()):
            if frq[n]==max(vlst):
                nlst.append(n)
        return nlst
print("최빈값은",mode(lst1),"입니다.") #26,37

a = [28, 30, 32, 34, 144]
if max(a)== min(a):
    print("없다.")
else:
    a.sort()
    b = 0
    for i in range(len(a)):
        if a[i-1] == a[i] :
            print(a[i])
        else:
            b += 1
            if b == int(len(a)):
                print("없다.")

N = list(map(int,input().split()))
M = {}
test = list()
for i in N:
    check = 0
    go = 0
    for j in range(len(test)):
        if test[j] == i:
            check = 1
            go = j
    if check == 0:
        M[i] = 1
        test.append(i)
    elif check == 1:
        M[test[go]] = M[test[go]] + 1

finalcheck = 0
usecheck = 0
for i in sorted(M.items(), key=lambda x: x[1], reverse=True):
    if usecheck != 0:
        if usecheck != list(i)[1]:
            break
    elif usecheck == 0:
        if list(i)[1] == 1:
            finalcheck = 1
            break
    usecheck = list(i)[1]
    print(str(list(i)[0]) + ' ', end='')
if finalcheck == 1:
    print("없다")

'''더 쉽게 하는 방법이 있을것 같긴 한데 
참 어렵게 문제를 풀었습니다. 
동작은 잘 하지만, 
별로 시원한 느낌이 들지 않는 코드입니다'''

import random
num=[]
numnum=random.randint(1,10)
for i in range (0,numnum):
    num.append(random.randint(1,10))

numdic={}
most=[]
max=0

for i in range (0,len(num)):
    if not num[i] in numdic:
        numdic[num[i]]=1
    else:
        numdic[num[i]]+=1

print()
for k,v in numdic.items():
    if v>max:
        max=v

print()
for k,v in numdic.items():
    if v==max:
        most.append(k)

print(num,' = ',end='')

if max==1 or max==len(num):
    print ('None')
else:
    for i in range (0,len(most)):
        print(most[i],' ',end='')

from collections import Counter
def mode(m):
    c = Counter(m)
    return '최빈값은 없다.' if len({v: k for k, v in c.items()}) == 1 \
    else [k for k, v in c.items() if max(c.values()) == v]

if __name__ == '__main__':
    m = [26, 37, 26, 37, 91]
    print(*mode(m))

import java.util.*;

public class a {
    public static void Mode(int[] num){
        Set<Integer> set1 = new HashSet<Integer>();
        for(int i=0;i<num.length;i++){
            set1.add(num[i]);
        }
        int[] set2 = new int[set1.size()];
        int b = 0;
        for(Integer x : set1) set2[b++] = x;

        ArrayList<Integer> d = new ArrayList<Integer>();
        for(int i=0;i<set2.length;i++){
            int c = 0;
            for(int j=0;j<num.length;j++){
                if(set2[i]==num[j]){
                    c = c + 1;
                }
            }
            d.add(i, c);
        }

        Integer e = Collections.max(d);
        ArrayList<Integer> set3 = new ArrayList<Integer>();
        for(int i=0;i<set2.length;i++){
            int c1 = 0;
            for(int j=0;j<num.length;j++){
                if(set2[i]==num[j]){
                    c1 = c1 + 1;
                }
            }
            if(c1==e){
                set3.add(set2[i]);
            }
        }
        System.out.println(set3);
    }

    public static void main(String[] args){
        int[] list1 = {12, 17, 19, 17, 23};
        int[] list2 = {26, 37, 26, 37, 91};
        int[] list3 = {28, 30, 32, 34, 144};
        Mode(list1);
        Mode(list2);
        Mode(list3);
    }
}

def print_mode(c):
    a = {i:c.count(i) for i in c}
    b = [n for n in a.keys()
        if a[n] == max(a.values()) and a[n] > 1]
    if b == []:
        b = ['없다']

    return "{0}".format(b)

c = [[12, 17, 19, 17, 23],[26, 37, 26, 37, 91],[28, 30, 32, 34, 144]]
for i in c:
    print(print_mode(i))

def Max_Count(data):
    d = {}
    key_value = set(data)
    for k in key_value:
        cnt = data.count(k)
        d[k]=cnt

    Max = 0
    result = []
    for i in d:        
        if Max < d[i] :
           Max = d[i]
           keys = i
        elif d[keys] == 1:
            return None
    for j in d:
        if d[keys] == d[j]:
            result.append(j)

    print(result)

Max_Count([12, 17, 19, 17, 23])
Max_Count([26, 37, 26, 37, 91])
Max_Count([28, 30, 32, 34, 144])

n = int(input("배열 크기"))
arr = []
for i in range(n):
    print(i+1,"번쨰")
    arr.append(int(input("원소 입력")))
set_arr = list(set(arr))        
cnt_arr = []
for k in set_arr:
    cnt_arr.append([arr.count(k),k])

max_cnt = max(cnt_arr)[0]

if len(set(arr))==len(arr):
    print("최빈값 없음")
else:
    for j in cnt_arr:
        if j[0] == max_cnt :
            print(j[1],end=", ")

집합을 이용해서 원소를 분리했습니다 [원소개소,원소] 를 2차배열에 담았고, 2차배열의 max값은 0번쨰 인덱스를 비교하는것을 이용했어요.

// Rust

// 자료형 변환 없이 HashMap으로 그냥 찾았습니다

use std::collections::HashMap; fn mode() {

let input = [[12, 17, 19, 17, 23],
                [26, 37, 26, 37, 91],
                [28, 30, 32, 34, 144],];
for list in input {
    let mut map: HashMap<u32, u32> = HashMap::new();
    for v in list {
        let count = map.entry(v).or_default();
        *count += 1;
    }

    // value max인 key 찾기
    let max_count = map.values().max().unwrap();
    let mut result = vec![];
    if *max_count != 1 { 
        result = map.iter().filter(|&(_,v)| *v==*max_count).collect();
    }
    println!("{:?}", result);
}

}

a = [28, 30, 32, 34, 144]
b = sorted(list(set(a)))
md = my_dict = {}

for i in b:
    md[i]=a.count(i)

max_count = max(md.values())

if max_count == 1 or max_count == len(a):
    print('없다.')
else:
    for value, count in md.items():
        if count == max(md.values()):
            print(value)

미숙한 코드입니다. 조언 부탁드려요

package org.javaturotials.ex;
import java.util.*;
import java.util.stream.Collectors;

public class test {
    public static void main(String[] args) {    
    int max=-1;
    int chm = 0;
        int[] arr = {26, 37, 26, 37, 91};
        int[] chc = new int[arr.length];
    int[] siz = new int[arr.length];
    for(int i=0; i<arr.length; i++) {
        int count=0;
        for(int j=0; j<arr.length; j++) {
            if(i!=j) {
                if(arr[i]==arr[j]) {
                    count++;
                }
            }
        }
        if(max<=count) {
            max=count;
            chc[i]=arr[i];
        }
        }

    System.out.print("최빈값은: ");
    for(int i=0; i<chc.length; i++) {
        if(chc[i]!=0) {
        System.out.print(chc[i] + " ");}
    }
    }
    }

자바로 풀어봤습니다.

import java.util.Scanner;
import java.util.ArrayList;

public class test {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        ArrayList<Integer> numbers = new ArrayList<>();

        // 입력 받기
        while(true) {
            System.out.print("숫자를 입력하시오: (그만 입력하고 싶으면 !을 입력하시오.)");
            String inputData = scan.next();

            if(inputData.equals("!")) {
                break;
            }else {
                numbers.add(Integer.parseInt(inputData));
            }
        }

        // 내림차순 정리
        int max, maxidx;
        for(int i=0; i<numbers.size(); i++) {
            max = numbers.get(i);
            maxidx=i;
            for(int j=i+1; j<numbers.size(); j++) {
                if(numbers.get(j)>max) {
                    maxidx=j;
                    max=numbers.get(j);
                }           
            }
            numbers.set(maxidx, numbers.get(i));
            numbers.set(i, max);
        }

        // 최빈값 구하기
        ArrayList<Integer> result = new ArrayList<>();
        result.add(numbers.get(0));
        int count=1, maxCount=1;

        for(int i=1; i<numbers.size(); i++) {
            if(numbers.get(i-1)!= numbers.get(i)) {
                if(count>maxCount) {
                    maxCount=count;
                    result.clear();
                    result.add(numbers.get(i-1));
                }else if(count==maxCount) {
                    result.add(numbers.get(i-1));
                }

                count = 1;
            }else {
                count++;
            }
        }

        if(count==maxCount) {
            result.add(numbers.get(numbers.size()-1));
        }

        // 빈도수에 따라 결과값 출력
        if(maxCount!=1) {
            System.out.println("최빈값:"+result+"\n");
            System.out.printf("빈도수는 %d입니다.", maxCount); 
        }else {
            System.out.println("최빈값 없다.");
        }


    }
}