# XOR of Prime Frequencies of Characters in a String

Given a string containing only lowercase english alphabets. The task is to find the bitwise XOR of all the prime frequencies of the characters in the string. If no prime frequency is present, then print -1.

Examples:

```Input : str = "gggggeeekkkks"
Output : 6

Input : str = "aabbbbw"
Output : -1
```

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

Approach:

Below is the implementation of the above approach:

## C++

 `// C++ program to find XOR of Prime ` `// Frequencies of Characters in a String ` `#include ` `using` `namespace` `std; ` ` `  `// Function to create Sieve to check primes ` `void` `SieveOfEratosthenes(``bool` `prime[], ``int` `p_size) ` `{ ` `    ``// false here indicates ` `    ``// that it is not prime ` `    ``prime = ``false``; ` `    ``prime = ``false``; ` ` `  `    ``for` `(``int` `p = 2; p * p <= p_size; p++) { ` ` `  `        ``// If prime[p] is not changed, ` `        ``// then it is a prime ` `        ``if` `(prime[p]) { ` ` `  `            ``// Update all multiples of p, ` `            ``// set them to non-prime ` `            ``for` `(``int` `i = p * 2; i <= p_size; i += p) ` `                ``prime[i] = ``false``; ` `        ``} ` `    ``} ` `} ` ` `  `// Function to find XOR of prime frequencies ` `int` `xorOfPrime(string s) ` `{ ` `    ``bool` `prime; ` `    ``memset``(prime, ``true``, ``sizeof``(prime)); ` ` `  `    ``SieveOfEratosthenes(prime, 10005); ` ` `  `    ``int` `i, j; ` ` `  `    ``// map is used to store character ` `    ``// frequencies ` `    ``map<``char``, ``int``> m; ` `    ``for` `(i = 0; i < s.length(); i++) ` `        ``m[s[i]]++; ` ` `  `    ``int` `result = 0; ` `    ``int` `flag = 0; ` ` `  `    ``// Traverse the map ` `    ``for` `(``auto` `it = m.begin(); it != m.end(); it++) { ` `        ``// Calculate XOR of all prime ` `        ``// frequencies ` `        ``if` `(prime[it->second]) { ` `            ``result ^= it->second; ` `            ``flag = 1; ` `        ``} ` `    ``} ` ` `  `    ``if` `(!flag) ` `        ``return` `-1; ` ` `  `    ``return` `result; ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``string s = ``"gggggeeekkkks"``; ` ` `  `    ``cout << xorOfPrime(s); ` ` `  `    ``return` `0; ` `} `

## Java

 `// Java program to find XOR of Prime ` `// Frequencies of Characters in a String ` `import` `java.util.*; ` ` `  `class` `GFG ` `{ ` ` `  `// Function to create Sieve to check primes ` `static` `void` `SieveOfEratosthenes(``boolean` `prime[], ``int` `p_size) ` `{ ` `    ``// false here indicates ` `    ``// that it is not prime ` `    ``prime[``0``] = ``false``; ` `    ``prime[``1``] = ``false``; ` ` `  `    ``for` `(``int` `p = ``2``; p * p <= p_size; p++) ` `    ``{ ` ` `  `        ``// If prime[p] is not changed, ` `        ``// then it is a prime ` `        ``if` `(prime[p]) ` `        ``{ ` ` `  `            ``// Update all multiples of p, ` `            ``// set them to non-prime ` `            ``for` `(``int` `i = p * ``2``; i <= p_size; i += p) ` `                ``prime[i] = ``false``; ` `        ``} ` `    ``} ` `} ` ` `  `// Function to find XOR of prime frequencies ` `static` `int` `xorOfPrime(``char``[] s) ` `{ ` `    ``boolean` `[]prime = ``new` `boolean``[``100005``]; ` `    ``for``(``int` `i = ``0``; i < ``100005``; i++) ` `        ``prime[i] = ``true``; ` ` `  `    ``SieveOfEratosthenes(prime, ``10005``); ` ` `  `    ``int` `i, j; ` ` `  `    ``// map is used to store character ` `    ``// frequencies ` `    ``Map m = ``new` `HashMap<>(); ` `    ``for` `(i = ``0``; i < s.length; i++) ` `    ``{ ` `        ``if``(m.containsKey(s[i])) ` `        ``{ ` `            ``m.put(s[i], m.get(s[i])+``1``); ` `        ``} ` `        ``else` `        ``{ ` `            ``m.put(s[i], ``1``); ` `        ``} ` `    ``} ` ` `  `    ``int` `result = ``0``; ` `    ``int` `flag = ``0``; ` ` `  `    ``// Traverse the map ` `    ``for` `(Map.Entry entry : m.entrySet()) ` `    ``{ ` `        ``// Calculate XOR of all prime ` `        ``// frequencies ` `        ``if` `(prime[entry.getValue()])  ` `        ``{ ` `            ``result ^= entry.getValue(); ` `            ``flag = ``1``; ` `        ``} ` `    ``} ` ` `  `    ``if` `(flag != ``1``) ` `        ``return` `-``1``; ` ` `  `    ``return` `result; ` `} ` ` `  `// Driver code ` `public` `static` `void` `main(String[] args)  ` `{ ` `    ``char``[] s = ``"gggggeeekkkks"``.toCharArray(); ` ` `  `    ``System.out.println(xorOfPrime(s)); ` `} ` `} ` ` `  `// This code has been contributed by 29AjayKumar `

## Python3

 `# Python3 program to find XOR of Prime  ` `# Frequencies of Characters in a String  ` `from` `collections ``import` `defaultdict ` ` `  `# Function to create Sieve to check primes  ` `def` `SieveOfEratosthenes(prime, p_size):  ` ` `  `    ``# False here indicates  ` `    ``# that it is not prime  ` `    ``prime[``0``] ``=` `False` `    ``prime[``1``] ``=` `False` `    ``p ``=` `2` ` `  `    ``while` `p ``*` `p <``=` `p_size:  ` ` `  `        ``# If prime[p] is not changed,  ` `        ``# then it is a prime  ` `        ``if` `prime[p]:  ` ` `  `            ``# Update all multiples of p,  ` `            ``# set them to non-prime  ` `            ``for` `i ``in` `range``(p ``*` `2``, p_size ``+` `1``, p):  ` `                ``prime[i] ``=` `False` `                 `  `        ``p ``+``=` `1` ` `  `# Function to find XOR of prime frequencies  ` `def` `xorOfPrime(s): ` ` `  `    ``prime ``=` `[``True``] ``*` `100005` `     `  `    ``SieveOfEratosthenes(prime, ``10005``)  ` ` `  `    ``# map is used to store character frequencies  ` `    ``m ``=` `defaultdict(``lambda``:``0``)  ` `    ``for` `i ``in` `range``(``0``, ``len``(s)):  ` `        ``m[s[i]] ``+``=` `1` ` `  `    ``result ``=` `flag ``=` `0` ` `  `    ``# Traverse the map  ` `    ``for` `it ``in` `m:  ` `         `  `        ``# Calculate XOR of all prime frequencies  ` `        ``if` `prime[m[it]]:  ` `            ``result ^``=` `m[it]  ` `            ``flag ``=` `1` `         `  `    ``if` `not` `flag:  ` `        ``return` `-``1` ` `  `    ``return` `result  ` ` `  `# Driver code  ` `if` `__name__ ``=``=` `"__main__"``:  ` ` `  `    ``s ``=` `"gggggeeekkkks"` ` `  `    ``print``(xorOfPrime(s))  ` ` `  `# This code is contributed by Rituraj Jain `

## C#

 `// C# program to find XOR of Prime ` `// Frequencies of Characters in a String ` `using` `System;      ` `using` `System.Collections.Generic; ` ` `  `class` `GFG ` `{ ` ` `  `// Function to create Sieve to check primes ` `static` `void` `SieveOfEratosthenes(Boolean []prime, ``int` `p_size) ` `{ ` `    ``// false here indicates ` `    ``// that it is not prime ` `    ``prime = ``false``; ` `    ``prime = ``false``; ` ` `  `    ``for` `(``int` `p = 2; p * p <= p_size; p++) ` `    ``{ ` ` `  `        ``// If prime[p] is not changed, ` `        ``// then it is a prime ` `        ``if` `(prime[p]) ` `        ``{ ` ` `  `            ``// Update all multiples of p, ` `            ``// set them to non-prime ` `            ``for` `(``int` `i = p * 2; i <= p_size; i += p) ` `                ``prime[i] = ``false``; ` `        ``} ` `    ``} ` `} ` ` `  `// Function to find XOR of prime frequencies ` `static` `int` `xorOfPrime(``char``[] s) ` `{ ` `    ``Boolean []prime = ``new` `Boolean; ` `    ``for``(``int` `i = 0; i < 100005; i++) ` `        ``prime[i] = ``true``; ` ` `  `    ``SieveOfEratosthenes(prime, 10005); ` ` `  `     `  ` `  `    ``// map is used to store character ` `    ``// frequencies ` `    ``Dictionary<``char``, ``int``> mp = ``new` `Dictionary<``char``,``int``>(); ` `    ``for` `(``int` `i = 0; i < s.Length; i++) ` `        ``{ ` `            ``if` `(mp.ContainsKey(s[i])) ` `            ``{ ` `                ``var` `v = mp[s[i]] + 1; ` `                ``mp.Remove(s[i]); ` `                ``mp.Add(s[i], v); ` `            ``}  ` `            ``else` `            ``{ ` `                ``mp.Add(s[i], 1); ` `            ``} ` `        ``} ` ` `  `    ``int` `result = 0; ` `    ``int` `flag = 0; ` ` `  `    ``// Traverse the map ` `    ``foreach``(KeyValuePair<``char``, ``int``> entry ``in` `mp) ` `    ``{ ` `        ``// Calculate XOR of all prime ` `        ``// frequencies ` `        ``if` `(prime[entry.Value])  ` `        ``{ ` `            ``result ^= entry.Value; ` `            ``flag = 1; ` `        ``} ` `    ``} ` ` `  `    ``if` `(flag != 1) ` `        ``return` `-1; ` ` `  `    ``return` `result; ` `} ` ` `  `// Driver code ` `public` `static` `void` `Main(String[] args)  ` `{ ` `    ``char``[] s = ``"gggggeeekkkks"``.ToCharArray(); ` ` `  `    ``Console.WriteLine(xorOfPrime(s)); ` `} ` `} ` ` `  `// This code contributed by Rajput-Ji `

Output:

```6
```

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