用素数和计数子数组

给定整数数组A []。任务是计算总和为(size> 1)的素数的总子数组。

例子：

Input : A[] = { 1, 2, 3, 4, 5 }
Output : 3
Subarrays are -> {1, 2}, {2, 3}, {3, 4}

Input : A = { 22, 33, 4, 1, 10 };
Output : 4

方法：生成所有可能的子数组并将其总和存储在向量中。迭代向量并检查总和是否为素数。是，增加计数。

您可以使用筛网筛查O(1)中的和是否为素数。

下面是上述方法的实现：

C++

// C++ program to count subarrays
// with Prime sum
  
#include 
using namespace std;
  
// Function to count subarrays
// with Prime sum
int primeSubarrays(int A[], int n)
{
    int max_val = int(pow(10, 7));
  
    // USE SIEVE TO FIND ALL PRIME NUMBERS LESS
    // THAN OR EQUAL TO max_val
    // Create a boolean array "prime[0..n]". A
    // value in prime[i] will finally be false
    // if i is Not a prime, else true.
    vector prime(max_val + 1, true);
  
    // Remaining part of SIEVE
    prime[0] = false;
    prime[1] = false;
    for (int p = 2; p * p <= max_val; p++) {
  
        // If prime[p] is not changed, then
        // it is a prime
        if (prime[p] == true) {
  
            // Update all multiples of p
            for (int i = p * 2; i <= max_val; i += p)
                prime[i] = false;
        }
    }
  
    int cnt = 0; // Initialize result
  
    // Traverse through the array
    for (int i = 0; i < n - 1; ++i) {
        int val = A[i];
        for (int j = i + 1; j < n; ++j) {
            val += A[j];
  
            if (prime[val])
                ++cnt;
        }
    }
  
    // return answer
    return cnt;
}
  
// Driver program
int main()
{
    int A[] = { 1, 2, 3, 4, 5 };
    int n = sizeof(A) / sizeof(A[0]);
  
    cout << primeSubarrays(A, n);
  
    return 0;
}

Java

// Java program to count subarrays 
// with Prime sum 
import java.util.*;
class Solution
{
    
// Function to count subarrays 
// with Prime sum 
static int primeSubarrays(int A[], int n) 
{ 
    int max_val = (int)(Math.pow(10, 7)); 
    
    // USE SIEVE TO FIND ALL PRIME NUMBERS LESS 
    // THAN OR EQUAL TO max_val 
    // Create a boolean array "prime[0..n]". A 
    // value in prime[i] will finally be false 
    // if i is Not a prime, else true. 
    Vector prime=new Vector(max_val + 1); 
  
      
    //initilize initial value
    for (int p = 0; p 

---

Python3

# Python3 program to count subarrays 
# with Prime sum 
  
# Function to count subarrays 
# with Prime sum 
def primeSubarrays(A, n):
  
    max_val = 10**7
  
    # USE SIEVE TO FIND ALL PRIME NUMBERS 
    # LESS THAN OR EQUAL TO max_val 
    # Create a boolean array "prime[0..n]". A 
    # value in prime[i] will finally be false 
    # if i is Not a prime, else true. 
    prime = [True] * (max_val + 1) 
  
    # Remaining part of SIEVE 
    prime[0] = False
    prime[1] = False
    for p in range(2, int(max_val**(0.5)) + 1): 
  
        # If prime[p] is not changed, then 
        # it is a prime 
        if prime[p] == True: 
  
            # Update all multiples of p 
            for i in range(2 * p, max_val + 1, p):
                prime[i] = False
          
    cnt = 0 # Initialize result 
  
    # Traverse through the array 
    for i in range(0, n - 1): 
        val = A[i] 
        for j in range(i + 1, n): 
            val += A[j] 
  
            if prime[val] == True: 
                cnt += 1
  
    # return answer 
    return cnt 
  
# Driver Code
if __name__ == "__main__":
  
    A = [1, 2, 3, 4, 5] 
    n = len(A) 
  
    print(primeSubarrays(A, n))
  
# This code is contributed by Rituraj Jain

C#

// C# program to count subarrays 
// with Prime sum 
  
class Solution
{
  
// Function to count subarrays 
// with Prime sum 
static int primeSubarrays(int[] A, int n) 
{ 
    int max_val = (int)(System.Math.Pow(10, 7)); 
  
    // USE SIEVE TO FIND ALL PRIME NUMBERS LESS 
    // THAN OR EQUAL TO max_val 
    // Create a boolean array "prime[0..n]". A 
    // value in prime[i] will finally be false 
    // if i is Not a prime, else true. 
    bool[] prime=new bool[max_val + 1]; 
  
      
    //initilize initial value
    for (int p = 0; p 

---

输出：

3

时间复杂度： O(N ² )