Substring de longitud máxima con la frecuencia más alta en una string

Dada una string. La tarea es encontrar la substring máxima ocurrida con una longitud máxima. Estas ocurrencias pueden superponerse.
Ejemplos: 

Input: str = "abab"
Output: ab
"a", "b", "ab" are occur 2 times. But, "ab" has maximum length

Input: str = "abcd"
Output: a

Enfoque: la idea es almacenar la frecuencia de cada substring usando un mapa e imprimir el que tiene la frecuencia máxima y la longitud máxima. 
A continuación se muestra la implementación del enfoque anterior: 
 

// C++ program to find maximum
// occurred substring of a string
#include <bits/stdc++.h>
using namespace std;
 
// function to return maximum
// occurred substring of a string
string MaxFreq(string str)
{
    // size of the string
    int n = str.size();
 
    unordered_map<string, int> m;
 
    for (int i = 0; i < n; i++) {
        string s = "";
        for (int j = i; j < n; j++) {
            s += str[j];
            m[s]++;
        }
    }
 
    // to store maximum frequency
    int maxi = 0;
 
    // to store string which has maximum frequency
    string s;
    for (auto i = m.begin(); i != m.end(); i++) {
        if (i->second > maxi) {
            maxi = i->second;
            s = i->first;
        }
        else if (i->second == maxi) {
            string ss = i->first;
            if (ss.size() > s.size())
                s = ss;
        }
    }
 
    // return substring which has maximum frequency
    return s;
}
 
// Driver program
int main()
{
    string str = "ababecdecd";
 
    // function call
    cout << MaxFreq(str);
 
    return 0;
}

// Java program to find maximum
// occurred subString of a String
import java.util.*;
class GFG{
 
// Function to return maximum
// occurred subString of a String
static String MaxFreq(String str)
{
  // Size of the String
  int n = str.length();
 
  Map<String,
      Integer> mp = new HashMap<String,
                                Integer>();
 
  for (int i = 0; i < n; i++)
  {
    String s = "";
    for (int j = i; j < n; j++)
    {
      s += str.charAt(j);
      if(mp.containsKey(s))
      {
        mp.put(s, mp.get(s) + 1);
      }
      else
      {
        mp.put(s, 1);
      }
    }
  }
 
  // To store maximum frequency
  int maxi = 0;
 
  // To store String which
  // has maximum frequency
  String s = "";
  for (Map.Entry<String,
                 Integer> i : mp.entrySet())
  {
    if (i.getValue() > maxi)
    {
      maxi = i.getValue();
      s = i.getKey();
    }
    else if (i.getValue() == maxi)
    {
      String ss = i.getKey();
      if (ss.length() > s.length())
        s = ss;
    }
  }
 
  // Return subString which
  // has maximum frequency
  return s;
}
 
// Driver code
public static void main(String[] args)
{
  String str = "ababecdecd";
 
  // Function call
  System.out.print(MaxFreq(str));
}
}
 
// This code is contributed by shikhasingrajput

# Python3 program to find maximum
# occurred of a string
 
# function to return maximum occurred
# substring of a string
def MaxFreq(s):
     
    # size of string
    n = len(s)
     
    m = dict()
     
    for i in range(n):
        string = ''
        for j in range(i, n):
            string += s[j]
            if string in m.keys():
                m[string] += 1
            else:
                m[string] = 1
                 
    # to store maximum frequency
    maxi = 0
     
    # To store string which has
    # maximum frequency
    maxi_str = ''
     
    for i in m:
        if m[i] > maxi:
            maxi = m[i]
            maxi_str = i
        elif m[i] == maxi:
            ss = i
            if len(ss) > len(maxi_str):
                maxi_str = ss
                 
    # return substring which has maximum freq
    return maxi_str
     
# Driver code
string = "ababecdecd"
 
print(MaxFreq(string))
         
# This code is contributed by Mohit kumar 29    

// C# program to find maximum
// occurred substring of a string
using System;
using System.Collections.Generic;
 
class GFG{
 
// Function to return maximum
// occurred substring of a string
static string MaxFreq(string str)
{
     
    // Size of the string
    int n = str.Length;
     
    Dictionary<string,
               int> m = new Dictionary<string,
                                       int>();
                         
    for(int i = 0; i < n; i++)
    {
        string sp = "";
        for(int j = i; j < n; j++)
        {
            sp += str[j];
            if(m.ContainsKey(sp))
            {
                m[sp]++;
            }
            else
            {
                m[sp] = 1;
            }
        }
    }
 
    // To store maximum frequency
    int maxi = 0;
 
    // To store string which has maximum frequency
    string s = "";
     
    foreach(KeyValuePair<string, int> i in m)
    {
        if (i.Value > maxi)
        {
            maxi = i.Value;
            s = i.Key;
        }
        else if (i.Value == maxi)
        {
            string ss = i.Key;
            if (ss.Length > s.Length)
                s = ss;
        }
    }
 
    // Return substring which has
    // maximum frequency
    return s;
}
 
// Driver Code
public static void Main(string[] args)
{
    string str = "ababecdecd";
 
    // Function call
    Console.Write(MaxFreq(str));
}
}
 
// This code is contributed by rutvik_56

<script>
 
// JavaScript program to find maximum
// occurred subString of a String
 
// Function to return maximum
// occurred subString of a String
function MaxFreq(str)
{
    // Size of the String
  let n = str.length;
  
  let mp = new Map();
  
  for (let i = 0; i < n; i++)
  {
    let s = "";
    for (let j = i; j < n; j++)
    {
      s += str[j];
      if(mp.has(s))
      {
        mp.set(s, mp.get(s) + 1);
      }
      else
      {
        mp.set(s, 1);
      }
    }
     }
  
  // To store maximum frequency
  let maxi = 0;
  
  // To store String which
  // has maximum frequency
  let s = "";
  for (let [key, value] of mp.entries())
  {
    if (value > maxi)
    {
      maxi = value;
      s = key;
    }
    else if (value == maxi)
    {
     let ss = key;
      if (ss.length > s.length)
        s = ss;
    }
  }
  
  // Return subString which
  // has maximum frequency
  return s;
}
 
 
// Driver code
 
let str = "ababecdecd";
 
// Function call
document.write(MaxFreq(str));
 
// This code is contributed by patel2127
 
</script>

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