# Maximum length substring with highest frequency in a string

Given a string. The task is to find the maximum occurred substring with a maximum length. These occurrences can overlap.

Examples:

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

Input: str = "abcd"
Output: a
```

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: The idea is to store the frequency of each substring using a map and print the one with maximum frequency and maximum length.

Below is the implementation of the above approach:

## C++

 `// CPP program to find maximum ` `// occurred substring of a string ` `#include ` `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 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; ` `} `

## Python3

 `# Python3 program to find maximum  ` `# occured 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): ` `        ``strng ``=` `'' ` `        ``for` `j ``in` `range``(i, n): ` `            ``strng ``+``=` `s[j] ` `            ``if` `strng ``in` `m.keys(): ` `                ``m[strng] ``+``=` `1` `            ``else``: ` `                ``m[strng] ``=` `1` `                 `  `    ``# to store maximum freqency ` `    ``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 ` `strng ``=` `"ababecdecd"` ` `  `print``(MaxFreq(strng)) ` `         `  `# This code is contributed by Mohit kumar 29      `

Output:

```ecd
```

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Improved By : mohit kumar 29