字符串中字符的主要频率的异或
给定一个只包含小写英文字母的字符串。任务是找到字符中所有主要频率的按位字符串或。如果不存在主频率，则打印 -1。
例子：
Input : str = "gggggeeekkkks"
Output : 6
Input : str = "aabbbbw"
Output : -1方法：
- 使用 map STL 遍历字符串并存储所有字符的频率。
- 使用埃拉托色尼筛法找出素数的频率。
- 计算所有这些主要频率的异或。
下面是上述方法的实现：
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[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
int 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 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 JainC#
// 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[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);
// map is used to store character
// frequencies
Dictionary mp = new Dictionary();
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 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 Javascript
输出：
6