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
Approach:
- Traverse the string and store the frequencies of all the characters using map STL.
- Find the frequencies which are prime numbers using Sieve Of Eratosthenes.
- Calculate XOR of all these prime frequencies.
Below is the implementation of the above approach:
C++
// C++ program to find XOR of Prime// Frequencies of Characters in a String#include <bits/stdc++.h>using namespace std;// Function to create Sieve to check primesvoid SieveOfEratosthenes(bool 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 frequenciesint xorOfPrime(string s){ bool prime[100005]; 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 codeint main(){ string s = "gggggeeekkkks"; cout << xorOfPrime(s); return 0;} |
Java
// Java program to find XOR of Prime// Frequencies of Characters in a Stringimport java.util.*;class GFG{// Function to create Sieve to check primesstatic 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 frequenciesstatic 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<Character,Integer> 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<Character,Integer> 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 codepublic 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 Stringusing System; using System.Collections.Generic;class GFG{// Function to create Sieve to check primesstatic 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 frequenciesstatic int xorOfPrime(char[] s){ Boolean []prime = new Boolean[100005]; 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 codepublic static void Main(String[] args) { char[] s = "gggggeeekkkks".ToCharArray(); Console.WriteLine(xorOfPrime(s));}}// This code contributed by Rajput-Ji |
Javascript
<script>// Javascript program to find XOR of Prime// Frequencies of Characters in a String// Function to create Sieve to check primesfunction SieveOfEratosthenes(prime, p_size){ // false here indicates // that it is not prime prime[0] = false; prime[1] = false; for (var 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 (var i = p * 2; i <= p_size; i += p) prime[i] = false; } }}// Function to find XOR of prime frequenciesfunction xorOfPrime(s){ var prime = Array(100005).fill(true); SieveOfEratosthenes(prime, 10005); var i, j; // map is used to store character // frequencies var m = new Map(); for (i = 0; i < s.length; i++) { if(m.has(s[i])) { m.set(s[i], m.get(s[i])+1); } else { m.set(s[i],1); } } var result = 0; var flag = 0; // Traverse the map m.forEach((value,key) => { // Calculate XOR of all prime // frequencies if (prime[value]) { result ^= value; flag = 1; } }); if (!flag) return -1; return result;}// Driver codevar s = "gggggeeekkkks";document.write( xorOfPrime(s));</script> |
Output
6
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