给定一个包含N 个正整数的链表，任务是从链表中找到所有完美数的和。
A number is perfect if is equal to the sum of its proper divisors i.e. the sum of its positive divisors excluding the number itself.
例子：
Input: L1 = 3 -> 6 -> 9
Output:6
Proper divisor sum of 3 = 1
ans=0
Proper divisor sum of 6 = 1 + 2 + 3 = 6
ans=6;
Proper divisor sum of 9 = 1 + 3 = 4
ans=6;
Input: L1 = 17 -> 6 -> 10 -> 6 -> 4
Output: 12
方法：初始化sum = 0并且对于列表的每个节点，找到其适当除数的总和，例如sumFactors 。如果cur_node = sumFactors则将结果总和更新为sum = sum + cur_node 。最后打印总和。
下面是上述方法的实现：
C++
// C++ implementation of the approach
#include
using namespace std;
// Node of the singly linked list
struct Node {
int data;
Node* next;
};
// Function to insert a node
// at the beginning of
// the singly Linked List
void push(Node** head_ref, int new_data)
{
// allocate node
Node* new_node
= (Node*)malloc(
sizeof(struct Node));
// put in the data
new_node->data = new_data;
// link the old list off the new node
new_node->next = (*head_ref);
// move the head to point
// to the new node
(*head_ref) = new_node;
}
// Function to return the sum of
// all the proper factors of n
int sumOfFactors(int n)
{
int sum = 0;
for (int f = 1; f <= n / 2; f++) {
// f is the factor of n
if (n % f == 0) {
sum += f;
}
}
return sum;
}
// Function to return the required sum
int getSum(Node* head_1)
{
// To store the sum
int sum = 0;
Node* ptr = head_1;
while (ptr != NULL) {
// If current element is non-zero
// and equal to the sum
// of proper factors of itself
if (ptr->data > 0
&& ptr->data
== sumOfFactors(ptr->data)) {
sum += ptr->data;
}
ptr = ptr->next;
}
return sum;
}
// Driver code
int main()
{
// start with the empty list
Node* head1 = NULL;
// create the linked list
push(&head1, 17);
push(&head1, 6);
push(&head1, 10);
push(&head1, 6);
push(&head1, 4);
int k = getSum(head1);
cout << k;
return 0;
} Java
// Java implementation of the approach
class GFG{
// Node of the singly linked list
static class Node
{
int data;
Node next;
};
// Function to insert a node
// at the beginning of
// the singly Linked List
static Node push(Node head_ref,
int new_data)
{
// Allocate node
Node new_node= new Node();
// Put in the data
new_node.data = new_data;
// Link the old list off the new node
new_node.next = head_ref;
// Move the head to point
// to the new node
head_ref = new_node;
return head_ref;
}
// Function to return the sum of
// all the proper factors of n
static int sumOfFactors(int n)
{
int sum = 0;
for(int f = 1; f <= n / 2; f++)
{
// f is the factor of n
if (n % f == 0)
{
sum += f;
}
}
return sum;
}
// Function to return the required sum
static int getSum(Node head_1)
{
// To store the sum
int sum = 0;
Node ptr = head_1;
while (ptr != null)
{
// If current element is non-zero
// and equal to the sum of proper
// factors of itself
if (ptr.data > 0 && ptr.data ==
sumOfFactors(ptr.data))
{
sum += ptr.data;
}
ptr = ptr.next;
}
return sum;
}
// Driver code
public static void main(String[] args)
{
// Start with the empty list
Node head = new Node();
// Create the linked list
head = push(head, 17);
head = push(head, 6);
head = push(head, 10);
head = push(head, 6);
head = push(head, 4);
int k = getSum(head);
System.out.print(k);
}
}
// This code is contributed by amal kumar choubeyPython3
# Python3 implementation of the approach
# Node class
class Node:
# Function to initialize the node object
def __init__(self, data):
self.data = data
self.next = None
# Linked List Class
class LinkedList:
# Function to initialize the
# LinkedList class.
def __init__(self):
self.head = None
# This function insert a new node at
# the beginning of the linked list
def push(self, new_data):
# Create a new Node
new_node = Node(new_data)
# Make next of new Node as head
new_node.next = self.head
# Move the head to point to new Node
self.head = new_node
# Function to return the required sum
def getSum(self):
# To store the sum
Sum = 0
# Initialising the pointer
ptr = self.head
while(True):
# If current element is non Zero
# and is a perfect number then
# add to sum
if(ptr.data > 0 and ptr.data ==
sumOfFactors(ptr.data)):
Sum += ptr.data
# Breaking the loop if list terminates
if(ptr.next == None):
break
# Moving to next node
ptr = ptr.next
# Returning the sum
return Sum
# Function to return the sum of
# all the proper factors of n
def sumOfFactors(n):
Sum = 0
# f is factor of n
for f in range(1, (n // 2) + 1):
if(n % f == 0):
Sum += f
return Sum
# Driver Code
if __name__=='__main__':
# Start with empty list
head1 = LinkedList()
# Create the linked list
head1.push(17)
head1.push(6)
head1.push(10)
head1.push(6)
head1.push(4)
# Getting the required sum
k = head1.getSum()
print(k)
# This code is contributed by Amit MangalC#
// C# implementation of the approach
using System;
class GFG{
// Node of the singly linked list
class Node
{
public int data;
public Node next;
};
// Function to insert a node
// at the beginning of
// the singly Linked List
static Node push(Node head_ref,
int new_data)
{
// Allocate node
Node new_node= new Node();
// Put in the data
new_node.data = new_data;
// Link the old list off the new node
new_node.next = head_ref;
// Move the head to point
// to the new node
head_ref = new_node;
return head_ref;
}
// Function to return the sum of
// all the proper factors of n
static int sumOfFactors(int n)
{
int sum = 0;
for(int f = 1; f <= n / 2; f++)
{
// f is the factor of n
if (n % f == 0)
{
sum += f;
}
}
return sum;
}
// Function to return the required sum
static int getSum(Node head_1)
{
// To store the sum
int sum = 0;
Node ptr = head_1;
while (ptr != null)
{
// If current element is non-zero
// and equal to the sum of proper
// factors of itself
if (ptr.data > 0 && ptr.data ==
sumOfFactors(ptr.data))
{
sum += ptr.data;
}
ptr = ptr.next;
}
return sum;
}
// Driver code
public static void Main(String[] args)
{
// Start with the empty list
Node head = new Node();
// Create the linked list
head = push(head, 17);
head = push(head, 6);
head = push(head, 10);
head = push(head, 6);
head = push(head, 4);
int k = getSum(head);
Console.Write(k);
}
}
// This code is contributed by amal kumar choubey输出：
12
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