📜  在 N 中查找任意数 P 的幂!

📅  最后修改于: 2021-09-04 09:36:57             🧑  作者: Mango

先决条件:打印所有质因数及其幂
给定自然数NP ,任务是在N的因式分解中找到P的幂 .
例子

朴素的方法:这个想法是找到从1 到 N 的每个数字的P的幂,然后将它们相加,正如我们在乘法幂相加过程中所知道的那样。
时间复杂度: O(N*P)
有效的方法:
N中数字P的幂请执行下列操作:

  1. 使用本文中讨论的方法找出数字P 的所有质因数及其频率。将主要因子及其频率存储在地图中。
  2. N的因式分解中找出P的每个素因数的幂通过使用本文中讨论的方法。
  3. 将上述步骤中获得的每个功率除以它们在图中对应的频率。
  4. 将上述步骤的结果存储在一个数组中,这些元素中的最小值将在 N! 的因式分解中给出P的幂。

下面是上述方法的实现:

C++
// C++ program to find the power
// of P in N!
#include 
using namespace std;
 
// Map to store all the prime
// factors of P
unordered_map Map;
 
// Function to find the prime
// factors of N im Map
void findPrimeFactors(int N)
{
    int i;
 
    // Clear map
    Map.clear();
 
    // Check for factors of 2
    while (N % 2 == 0) {
        Map[2] += 1;
        N /= 2;
    }
 
    // Find all the prime factors
    for (i = 3; i <= sqrt(N); i += 2) {
 
        // If i is a factors
        // then increase the
        // frequency of i
        while (N % i == 0) {
            Map[i] += 1;
            N /= i;
        }
    }
 
    if (N > 2) {
        Map[N] += 1;
    }
}
 
// Function to find the power
// of prime number P in N!
int PowInFactN(int N, int P)
{
    int ans = 0;
    int temp = P;
 
    // Loop until temp <= N
    while (temp <= N) {
 
        // Add the number of
        // numbers divisible
        // by N
        ans += N / temp;
 
        // Each time multiply
        // temp by P
        temp = temp * P;
    }
 
    // Returns ans
    return ans;
}
 
// Function that find the
// powers of any P in N!
int findPowers(int N, int P)
{
 
    // Find all prime factors
    // of number P
    findPrimeFactors(P);
 
    // To store the powers of
    // all prime factors
    vector Powers;
 
    // Traverse the map
    for (auto& it : Map) {
 
        // Prime factor and
        // corres. powers
        int primeFac = it.first;
        int facPow = it.second;
 
        // Find power of prime
        // factor primeFac
        int p = PowInFactN(N,
                           primeFac);
 
        // Divide frequency by
        // facPow
        p /= facPow;
 
        // Store the power of
        // primeFac^facPow
        Powers.push_back(p);
    }
 
    // Return the minimum
    // element in Power array
    return *min_element(Powers.begin(),
                        Powers.end());
}
 
// Driver's Code
int main()
{
    int N = 24, P = 4;
 
    // Function to find power of
    // P in N!
    cout << findPowers(N, P);
    return 0;
}


Java
// Java program to find the power
// of P in N!
import java.util.*;
 
class GFG{
  
// Map to store all the prime
// factors of P
static HashMap Map = new HashMap();
  
// Function to find the prime
// factors of N im Map
static void findPrimeFactors(int N)
{
    int i;
  
    // Clear map
    Map.clear();
  
    // Check for factors of 2
    while (N % 2 == 0) {
        if(Map.containsKey(2))
            Map.put(2, Map.get(2) + 1);
        else
            Map.put(2, 1);
        N /= 2;
    }
  
    // Find all the prime factors
    for (i = 3; i <= Math.sqrt(N); i += 2) {
  
        // If i is a factors
        // then increase the
        // frequency of i
        while (N % i == 0) {
            if(Map.containsKey(i))
                Map.put(i, Map.get(i) + 1);
            else
                Map.put(i, 1);
            N /= i;
        }
    }
  
    if (N > 2) {
        if(Map.containsKey(N))
            Map.put(N, Map.get(N) + 1);
        else
            Map.put(N, 1);
    }
}
  
// Function to find the power
// of prime number P in N!
static int PowInFactN(int N, int P)
{
    int ans = 0;
    int temp = P;
  
    // Loop until temp <= N
    while (temp <= N) {
  
        // Add the number of
        // numbers divisible
        // by N
        ans += N / temp;
  
        // Each time multiply
        // temp by P
        temp = temp * P;
    }
  
    // Returns ans
    return ans;
}
  
// Function that find the
// powers of any P in N!
static int findPowers(int N, int P)
{
  
    // Find all prime factors
    // of number P
    findPrimeFactors(P);
  
    // To store the powers of
    // all prime factors
    Vector Powers = new Vector();
  
    // Traverse the map
    for (Map.Entry it : Map.entrySet()) {
  
        // Prime factor and
        // corres. powers
        int primeFac = it.getKey();
        int facPow = it.getValue();
  
        // Find power of prime
        // factor primeFac
        int p = PowInFactN(N,
                           primeFac);
  
        // Divide frequency by
        // facPow
        p /= facPow;
  
        // Store the power of
        // primeFac^facPow
        Powers.add(p);
    }
  
    // Return the minimum
    // element in Power array
    return Collections.min(Powers);
}
  
// Driver's Code
public static void main(String[] args)
{
    int N = 24, P = 4;
  
    // Function to find power of
    // P in N!
    System.out.print(findPowers(N, P));
}
}
 
// This code is contributed by Rajput-Ji


Python3
# Python3 program to find the power
# of P in N!
import math
 
# Map to store all
# the prime factors of P
Map = {}
 
# Function to find the prime
# factors of N im Map
def findPrimeFactors(N):
 
    # Clear map
    Map.clear()
 
    # Check for factors of 2
    while (N % 2 == 0):
        if 2 in Map:
            Map[2] += 1
        else:
            Map[2] = 1
        N = N // 2
 
    # Find all the prime factors
    for i in range(3, int(math.sqrt(N)) + 1, 2):
       
        # If i is a factors
        # then increase the
        # frequency of i
        while (N % i == 0):
            if i in Map:
                Map[i] += 1
            else:
                Map[i] = 1
                 
            N = N // i
 
    if (N > 2):
        if N in Map:
            Map[N] += 1
        else:
            Map[N] = 1
 
# Function to find the power
# of prime number P in N!
def PowInFactN(N, P):
 
    ans = 0
    temp = P
 
    # Loop until temp <= N
    while (temp <= N):
 
        # Add the number of
        # numbers divisible
        # by N
        ans = ans + (N // temp)
 
        # Each time multiply
        # temp by P
        temp = temp * P
 
    # Returns ans
    return ans
 
# Function that find the
# powers of any P in N!
def findPowers(N, P):
 
    # Find all prime factors
    # of number P
    findPrimeFactors(P)
 
    # To store the powers of
    # all prime factors
    Powers = []
 
    # Traverse the map
    for it1, it2 in Map.items():
 
        # Prime factor and
        # corres. powers
        primeFac = it1
        facPow = it2
 
        # Find power of prime
        # factor primeFac
        p = PowInFactN(N, primeFac)
 
        # Divide frequency by
        # facPow
        p = p // facPow
 
        # Store the power of
        # primeFac^facPow
        Powers.append(p)
 
    # Return the minimum
    # element in Power array
    return min(Powers)
 
N, P = 24, 4
 
# Driver code
if __name__ == "__main__":
   
  # Function to find
  # power of P in N!
  print(findPowers(N, P))
 
# This code is contriibuted by divyeshrabadiya07


C#
// C# program to find the power
// of P in N!
using System;
using System.Linq;
using System.Collections.Generic;
 
class GFG{
 
// Map to store all the prime
// factors of P
static Dictionary Map = new Dictionary();
 
// Function to find the prime
// factors of N im Map
static void findPrimeFactors(int N)
{
    int i;
 
    // Clear map
    Map.Clear();
 
    // Check for factors of 2
    while (N % 2 == 0) {
        if(Map.ContainsKey(2))
            Map[2] = Map[2] + 1;
        else
            Map.Add(2, 1);
        N /= 2;
    }
 
    // Find all the prime factors
    for (i = 3; i <= Math.Sqrt(N); i += 2) {
 
        // If i is a factors
        // then increase the
        // frequency of i
        while (N % i == 0) {
            if(Map.ContainsKey(i))
                Map[i] = Map[i] + 1;
            else
                Map.Add(i, 1);
            N /= i;
        }
    }
 
    if (N > 2) {
        if(Map.ContainsKey(N))
            Map[N] =Map[N] + 1;
        else
            Map.Add(N, 1);
    }
}
 
// Function to find the power
// of prime number P in N!
static int PowInFactN(int N, int P)
{
    int ans = 0;
    int temp = P;
 
    // Loop until temp <= N
    while (temp <= N) {
 
        // Add the number of
        // numbers divisible
        // by N
        ans += N / temp;
 
        // Each time multiply
        // temp by P
        temp = temp * P;
    }
 
    // Returns ans
    return ans;
}
 
// Function that find the
// powers of any P in N!
static int findPowers(int N, int P)
{
 
    // Find all prime factors
    // of number P
    findPrimeFactors(P);
 
    // To store the powers of
    // all prime factors
    List Powers = new List();
 
    // Traverse the map
    foreach (KeyValuePair it in Map) {
 
        // Prime factor and
        // corres. powers
        int primeFac = it.Key;
        int facPow = it.Value;
 
        // Find power of prime
        // factor primeFac
        int p = PowInFactN(N,
                        primeFac);
 
        // Divide frequency by
        // facPow
        p /= facPow;
 
        // Store the power of
        // primeFac^facPow
        Powers.Add(p);
    }
 
    // Return the minimum
    // element in Power array
    return Powers.Min();
}
 
// Driver's Code
public static void Main(String[] args)
{
    int N = 24, P = 4;
 
    // Function to find power of
    // P in N!
    Console.Write(findPowers(N, P));
}
}
 
// This code is contributed by sapnasingh4991


输出:

11

时间复杂度: O(sqrt(P)*(log P N))

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