Linked List Deletion - Amazon Top Interview Questions

Problem Statement :

Given a singly linked list node, and an integer target, return the same linked list with all nodes whose value is target removed.


n ≤ 100,000 where n is the number of nodes in node

Example 1


node = [0, 1, 1, 2]
target = 1


[0, 2]

Solution :


                        Solution in C++ :

** Recursive

LLNode* solve(LLNode* node, int target) {
    if(not node) return node;
    node->next = solve(node->next, target);
    return node->val == target ? node->next : node;

** Iterative

LLNode* solve(LLNode* head, int target) {
    auto* node = head;
    while (node) {
        while (node->next && node->next->val == target) {
            node->next = node->next->next;
        node = node->next;
    return (head->val == target ? head->next : head);

                        Solution in Java :

import java.util.*;

 * class LLNode {
 *   int val;
 *   LLNode next;
 * }
class Solution {
    public LLNode solve(LLNode node, int target) {
        LLNode prev = node;
        LLNode cur =;
        while (cur != null) {
            LLNode nxt =;
            if (cur.val == target)
       = nxt;
            else {
                prev = cur;
            cur = nxt;
        if (node.val == target)
        return node;

                        Solution in Python : 
class Solution:
    def solve(self, node, target):
        while node != None and node.val == target:
            node =
        ret = node
        while node != None:
            while != None and == target:
            node =
        return ret

View More Similar Problems

Balanced Forest

Greg has a tree of nodes containing integer data. He wants to insert a node with some non-zero integer value somewhere into the tree. His goal is to be able to cut two edges and have the values of each of the three new trees sum to the same amount. This is called a balanced forest. Being frugal, the data value he inserts should be minimal. Determine the minimal amount that a new node can have to a

View Solution →

Jenny's Subtrees

Jenny loves experimenting with trees. Her favorite tree has n nodes connected by n - 1 edges, and each edge is ` unit in length. She wants to cut a subtree (i.e., a connected part of the original tree) of radius r from this tree by performing the following two steps: 1. Choose a node, x , from the tree. 2. Cut a subtree consisting of all nodes which are not further than r units from node x .

View Solution →

Tree Coordinates

We consider metric space to be a pair, , where is a set and such that the following conditions hold: where is the distance between points and . Let's define the product of two metric spaces, , to be such that: , where , . So, it follows logically that is also a metric space. We then define squared metric space, , to be the product of a metric space multiplied with itself: . For

View Solution →

Array Pairs

Consider an array of n integers, A = [ a1, a2, . . . . an] . Find and print the total number of (i , j) pairs such that ai * aj <= max(ai, ai+1, . . . aj) where i < j. Input Format The first line contains an integer, n , denoting the number of elements in the array. The second line consists of n space-separated integers describing the respective values of a1, a2 , . . . an .

View Solution →

Self Balancing Tree

An AVL tree (Georgy Adelson-Velsky and Landis' tree, named after the inventors) is a self-balancing binary search tree. In an AVL tree, the heights of the two child subtrees of any node differ by at most one; if at any time they differ by more than one, rebalancing is done to restore this property. We define balance factor for each node as : balanceFactor = height(left subtree) - height(righ

View Solution →

Array and simple queries

Given two numbers N and M. N indicates the number of elements in the array A[](1-indexed) and M indicates number of queries. You need to perform two types of queries on the array A[] . You are given queries. Queries can be of two types, type 1 and type 2. Type 1 queries are represented as 1 i j : Modify the given array by removing elements from i to j and adding them to the front. Ty

View Solution →