## Arrays Interview Questions

- 0of 0 votes
Write a logic to print the elements of 2D matrix in a spiral way?

for eg if int[][] matrix = {{1,2,3,4}{5.6,7,8}{9, 10, 11,12}};

The output should be 1 2 3 4 8 12 11 10 9 5 6 7

The interviewer asked me to implement a recursive algorithm.

- 0of 0 votes
You have a long string that contains of 0's and 1's, seprated with some delimiter (like "!"). the number of delimeters after each 0 or 1 is between 1 to 3.

for example a string such as 0! 1!!! 0!! 1!! 0! 1! 0!!! 1!! 0!! (and so on...)

Take this long string and convert it to a 7 digits number by some porgramming algorythem,

(you can use every lanugage you want)

- 1of 3 votes

- 0of 0 votes
Can multiple threads improve the time complexity to merge k sorted arrays? If so, how?

- 1of 1 vote
Write a function that takes an array of positive and negative integers and a number. This function should return true if the array contains a contiguous sub array that sums up to the number (2nd input).

He wanted an O(n) algorithm.

- 0of 0 votes
You are given an array of nodes where each node consists of node name, isValid flag, and parent Node index. so, this array actually represents a tree(forest). where root node has -1 as its index for the parent node. rest all node have their parent's index value.

You will be given this array and an index. You have to cut down the subtree from the index. Cutting down a tree means, making all the nodes of that subtree false(Isvalid flag).

He was expecting O(N) solution.

- 1of 1 vote
Q 1. You are given an array of integers, contains positive, negative and zeros. You have to written subarray whose sum is maximum in this array.

Desired Complexity is O(N) + O(1)

- -1of 1 vote
You are given an array of integers and a number K. You have to find the any continue sub-array whose elements sum is K. Please note that, the array may have positive, negative, and zeros as its element.

The desired complexity is O(N).

Example:

Input: [7 0 9 -10 0 789], K = 0

Output: Array from index 1 to Index 1.

Input: [1 2 3 5 -10] K = 0

Output: Array from Index 1 to Index 4.

If K = -2, Output would have been SubArray from Index 2 to Index 4.

- 0of 0 votes
You are given an integer array. You have to return/print an array where kth element of this array is the multiplications of all the elements from 0 to k-1 and from k+1 to n-1.

Example

input: [1 2 5 6]

output: [60 30 12 10]

- 0of 0 votes
You are given a rotated sorted array of size N. You have to search a given number into it.

Example: [4,6,8,14,90,-9,-2,0,3], Search -2.

- 0of 0 votes
Write a program which takes input a sorted array and positive number and updates the array so that if x appears m times in array then it appears exactly min(2,m) times in array. the update should be performed in one pass with no additional memory

- 0of 0 votes
You are given a vector of integers. You have to delete the odd numbers from it.

Expected complexity is O(N) Time and O(1) space

- 1of 3 votes
Given array of length n, having element 0 to n-1.

you are allowed to swap adjacent element only if Absolute difference of two element is equal to 1.

Is it possible to sort array.

If yes print sorted output.

- 0of 0 votes
Given an array of unique numbers. Find the number of pairs that make up the difference. This must be solved in under O(N^2)

`function getPairs(int[] array, int k){ HashMap<Integer,Integer> values = new HashMap<Integer,Integer>(); for(int i = 0; i < array.length; i++){ if(!values.containsKey(array[i])){ values.put(array[i],1); } } int pairs = 0; for(int i = 0; i < array.length; i++){ int diff = array[i] - k; if(values.containsKey(diff)){ pairs++; } } return pairs; }`

This will give O(N) time. O(N) Space

- 0of 0 votes
One question containing multiple questions

1) Define the structure of a function which takes an array of size n as input and returns True or False.

2) Write a function which takes an array as input and returns a string containing all the elements separated by a comma.

Ex : [0, -45, 9, 10] => "0,-45,9,10";

3) Write a function which takes two arrays ass input, and returns minimum common element in them.

Ex : [0, -90, 45, 10, 4], [4, 8, 90, 45] => 4

4) Now let's say, the function takes an array of arrays, and each array is sorted. now, returns their first common element.

Ex : [0, -90, 45, 10, 4], [4, 8, 90, 45], [-1, -3, -5, -7, 10, 4], [24, 35, 78, -90, 56, 4] => 4

- -2of 4 votes
Find the frequency of a number in array in less than bigo n time

Array 1,2,2,3,4,5,5,5,2

Input 5

Output 3

Array 1,1,1,1,

Input 1

Output 4

Keep in mind less than bigo n

Thanks

- -5of 5 votes
Fill the arrray with elements from 0 to 9.

based on thier frequency.

a[1]=3 means, 1 is repeated for 3 times(1 must present 3 times in that array)

a[2]=4 means 2 is repeated for 4 times.(2 must present twice in that array)

- 0of 0 votes
what is the best way to pass multi dimensional arrays to a function in c/c++.(dont say pointers is best, write the best syntax)

How will you read and write a matrix, with row and column number using STL.

- 0of 0 votes
Amezon_interview_3rd round:

Fill the arrray with elements from 0 to 9.

based on thier frequency.

a[1]=3 means, 1 is repeated for 3 times(1 must present 3 times in that array)

a[2]=4 means 2 is repeated for 4 times.(2 must present twice in that array)

- 0of 0 votes
You are given a string S consisting of N brackets, opening "("

and/or closing ")". The goal is to split S into two parts (left and

right), such that the number of opening brackets in the left part is

equal to the number of closing brackets in the right part.

For example, given S = "(())", the function should return 2,

because:

the first two characters of S, "((", contain two

opening brackets, and

the remaining two characters of S, "))", contain

two closing brackets.

In other example, given S = "(())))(", the function should return

4, because:

the first four characters of S, "(())", contain two

opening brackets, and

the remaining three characters of S, "))(", contain

two closing brackets.

In other example, given S = "))", the function should return 2,

because:

the first two characters of S, "))", contain zero

opening brackets, and

there are no remaining characters, so they contain

also zero closing brackets.

- -1of 1 vote
Given two strings representing very large integer numbers, find the Product. Do not use BigInt.

`using System; public class Program { public static void Main() { Console.WriteLine( GetProduct("18888888888888888888888888","19999999999999999999999999999999999999999999999999999999999")); } public static string GetProduct(string s1,string s2) { int digit1=0; int digit2=0; char[] str1=s1.ToCharArray(); char[] str2=s2.ToCharArray(); int carry; string[] result=new string[str1.Length]; string finalproduct=string.Empty; int padding=0; for(int i=str1.Length-1;i>=0;i--) { digit1=str1[i]-'0'; string resval=string.Empty; carry=0; int j; for(j=str2.Length-1;j>=0;j--) { digit2=str2[j]-'0'; int product=digit1*digit2+carry; carry=product/10; resval=resval+(product%10); } if(carry>0) { resval=resval+carry; } for(int k=0;k<padding;k++) { resval="0"+resval; } result[i]=resval; padding++; } int max=findMax(result); int count=0; int car=0; while(count<max) { int sum=0; for(int x=0;x<result.Length;x++) { if(count<result[x].Length) { sum+=result[x][count]-'0'; } } sum+=car; car=sum/10; int p=sum%10; finalproduct=p+finalproduct; count++; } finalproduct=car+finalproduct; return finalproduct.TrimStart('0'); } public static int findMax(string[] s) { int max=0; for(int i=0;i<s.Length;i++) { int len=s[i].Length; max=Math.Max(max,len); } return max; }`

}

- 0of 0 votes
Given a array of integers {-6,-3,-1,2,4,5} which are sorted .Sort square of the numbers .Output {1,4,9,16,25,36}

- -1of 3 votes
You have L, a list containing some digits (0 to 9). Write a function answer(L) which finds the largest number that can be made from some or all of these digits and is divisible by 3. If it is not possible to make such a number, return 0 as the answer. L will contain anywhere from 1 to 9 digits. The same digit may appear multiple times in the list, but each element in the list may only be used once.

{{

Test cases

==========

Inputs:

(int list) l = [3, 1, 4, 1]

Output:

(int) 4311

Inputs:

(int list) l = [3, 1, 4, 1, 5, 9]

Output:

(int) 94311

}}

My Solution:

{{

package com.google.challenges;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;

public class Answer {

public static int answer(int[] l) {

// Your code goes here.

ArrayList<Integer> list0 = new ArrayList<>();

ArrayList<Integer> list1 = new ArrayList<>();

ArrayList<Integer> list2 = new ArrayList<>();

int sum =0;

Arrays.sort(l);

for(int i = 0; i<l.length; i++){

if(l[i] % 3 == 0){

list0.add(l[i]);

}else if(l[i] % 3 == 1){

list1.add(l[i]);

}else{

list2.add(l[i]);

}

sum += l[i];

}

if(sum%3==0){

StringBuilder strNum = new StringBuilder();

for(int i = l.length-1; i >= 0; i--)

{

strNum.append(l[i]);

}

return Integer.parseInt(strNum.toString());

}else if(sum%3 == 1){

if(list1.size()>0){

Collections.sort(list1);

list1.remove(0);

}else if(list2.size() >= 2){

Collections.sort(list2);

list2.remove(1);

list2.remove(0);

}else{

return -1;

}

}else if(sum%3 == 2){

if(list2.size()>0){

Collections.sort(list2);

list2.remove(0);

}else if(list1.size() >= 2){

Collections.sort(list1);

list1.remove(1);

list1.remove(0);

}else{

return -1;

}

}

list0.addAll(list1);

list0.addAll(list2);

StringBuilder strNum = new StringBuilder();

Collections.sort(list0);

for(int i = list0.size()-1; i >= 0; i--)

{

strNum.append(list0.get(i));

}

return strNum.length() > 0 ? Integer.parseInt(strNum.toString()) : -1;

}

}

}}

But here I am able to pass 4 test cases out of 5. Therefore I am looking for scenario which is left to check.

Can someone help me?

- -1of 1 vote
I was asked the following: Given integers N and A. Find how many integer sequences with elements between 1 and A have sum of all elements equals to N.

N, A <= 1000.

Sample input: 4 3 , sample output is 7.

In this moment, I realized I do not understand the question. If I have a sequence of 1,2,3, the only sub-sequence that sums 4 is 1,3. So the answer should be 1. What am I missing?

Thank you

- 0of 0 votes
Given an array of integers, design an algorithm that moves all non-zero integers to the end of the array. Minimize the number of writes or swaps.

- 1of 1 vote
You are given an array of integers(with all valid input) You have to write a function which will produce another array, where the value in each index of the array will be the product of all values in the given array accept that index.

Example

Array 1: 1 2 3 4 5

Array 2: 120 60 40 30 24.

Come up with a solution of O(n^2) can you improve it?

- 0of 0 votes
Given an array of random numbers, shuffle the numbers once again with the least possibility of it being same as previous configuration.

- 0of 0 votes
Q. Given an array of numbers. Print all the pairs (2) of numbers in the array if the sum of those numbers is also present in the array. Write in C

- 1of 1 vote
Return the pivot index of the given array of numbers. The pivot index is the index where the sum of the numbers on the left is equal to the sum of the numbers on the right. Input Array {1,2,3,4,0,6}

- 0of 0 votes
You are given an array of positive and negative integers. If a number n at an index is positive, then move forward n steps. Conversely, if it's negative, move backward n steps. Determine if there is a loop in this array.

For example, given the array [2, -1, 1, 2, 2], index 0 maps to index 2, 1 maps to 0, 2 maps to 3, and so on. There is a loop in this array because 0 maps to 2, 2 maps to 3, and 3 maps to 0 (use the modulo operator).