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Modify Linked List by replacing each node by nearest multiple of K
• Last Updated : 26 Apr, 2021

Given a singly Linked List L consisting of N nodes and an integer K, the task is to modify the value of each node of the given Linked List to its nearest multiple of K, not exceeding the value of the node.

Examples:

Input: LL: 1 -> 2 -> 3 -> 5, K = 2
Output: 0 -> 2 -> 2 -> 4
Explanation:
The resultant LL has values having less than the original LL value and is a multiple of K(= 2).

Input: LL:13 -> 14 -> 26 -> 29 -> 40, K = 13
Output: 13 -> 13 -> 26 -> 26 -> 39

Approach: The given problem can be solved by traversing the given Linked List and for each node traversed, find the floor value, say val, of the node value divided by K and update the node values to val*K.

Below is the implementation of the above approach:

## C++

 `// C++ program for the above approach` `#include ``using` `namespace` `std;` `// Structure of node``struct` `node {``    ``int` `data;``    ``node* next;``};` `// Function to replace the node N``// by the nearest multiple of K``node* EvalNearestMult(node* N, ``int` `K)``{``    ``node* temp = N;``    ``int` `t;` `    ``// Traverse the Linked List``    ``while` `(N != NULL) {` `        ``// If data is less than K``        ``if` `(N->data < K)``            ``N->data = 0;` `        ``else` `{` `            ``// If the data of current``            ``// node is same as K``            ``if` `(N->data == K)``                ``N->data = K;` `            ``// Otherwise change the value``            ``else` `{``                ``N->data = (N->data / K) * K;``            ``}``        ``}` `        ``// Move to the next node``        ``N = N->next;``    ``}` `    ``// Return the updated LL``    ``return` `temp;``}` `// Function to print the nodes of``// the Linked List``void` `printList(node* N)``{``    ``// Traverse the LL``    ``while` `(N != NULL) {` `        ``// Print the node's data``        ``cout << N->data << ``"  "``;``        ``N = N->next;``    ``}``}` `// Driver Code``int` `main()``{``    ``// Given Linked List``    ``node* head = NULL;``    ``node* second = NULL;``    ``node* third = NULL;` `    ``head = ``new` `node();``    ``second = ``new` `node();``    ``third = ``new` `node();` `    ``head->data = 3;``    ``head->next = second;``    ``second->data = 4;``    ``second->next = third;``    ``third->data = 8;``    ``third->next = NULL;` `    ``node* t = EvalNearestMult(head, 3);` `    ``printList(t);` `    ``return` `0;``}`

## Java

 `// Java program for the above approach``import` `java.io.*;` `class` `GFG {` `    ``// Structure of node``    ``static` `class` `node {``        ``int` `data;``        ``node next;` `        ``node(``int` `d)``        ``{``            ``data = d;``        ``}``    ``}` `    ``// Function to replace the node N``    ``// by the nearest multiple of K``    ``static` `node EvalNearestMult(node N, ``int` `K)``    ``{``        ``node temp = N;``        ``int` `t;` `        ``// Traverse the Linked List``        ``while` `(N != ``null``) {` `            ``// If data is less than K``            ``if` `(N.data < K)``                ``N.data = ``0``;` `            ``else` `{` `                ``// If the data of current``                ``// node is same as K``                ``if` `(N.data == K)``                    ``N.data = K;` `                ``// Otherwise change the value``                ``else` `{``                    ``N.data = (N.data / K) * K;``                ``}``            ``}` `            ``// Move to the next node``            ``N = N.next;``        ``}` `        ``// Return the updated LL``        ``return` `temp;``    ``}` `    ``// Function to print the nodes of``    ``// the Linked List``    ``static` `void` `printList(node N)``    ``{``        ``// Traverse the LL``        ``while` `(N != ``null``) {` `            ``// Print the node's data``            ``System.out.print(N.data + ``"  "``);``            ``N = N.next;``        ``}``    ``}` `    ``// Driver Code``    ``public` `static` `void` `main(String[] args)``    ``{``        ``// Given Linked List``        ``node head = ``new` `node(``3``);``        ``head.next = ``new` `node(``5``);``          ``head.next.next = ``new` `node(``8``);` `        ``node t = EvalNearestMult(head, ``3``);` `        ``printList(t);``    ``}``}` `// This code is contributed by Dharanendra L V`
Output:
`3  3  6`

Time Complexity: O(N)
Auxiliary Space: O(1)

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