Amazon Interview Questions
- 0of 0 votes
AnswerGive an N-length array with only 0 and 1 inside
- ajay.raj May 01, 2018 in United States
Requires to find the minimum number of conversions needed to convert the array to 0 before all 1.
The conversion is to change a 0 to 1 or a 1 to 0,
And the number of 0 and 1 in the converted array can be arbitrary.
Just find the minimum conversion step| Report Duplicate | Flag | PURGE
Amazon SDE1 - 0of 0 votes
AnswersImagine a horizontal corridor bounded by y = y1 and y = y2 lines on a 2D-plane. There are N sensors with centers (x, y) each of which operates in a range (r) on the plane . So, they cover some circular areas on the plane. See the figure below.
o | _____o___o__|____________ y = y1 o |OOO __________oo|_____O______ y = y2 O | O _ _ _ _ _ _ | _ _ _ _ _ _ | o O | o O O | | O | |
The question is whether a path exist from x=-inf to x=+inf via corridor without being detected any radar.
Constraints:
1. You are free to move any direction only if you stay in the corridor.
2. You are free to go through corridor borders.
3. N sensors are given as list of (x, y, r) like [(1, 3, 2), (-1, -3, 4)]. x and y are signed integers. r is a unsigned integer.
4. y1 and y2 are integers.
My solution:
1. Create an intersection graph of N sensors by comparing them each other via Euclidean distance(x1 - x2)^2 + (y1 - y2)^2 <= (r1 + r2)^2
2. If there is a path between y=y1 and y=y2 through intersected sensors, there do not exist any path from x=-inf to x=+inf. Otherwise, there do exist a path. So, I used BFS to search such a path.
Worst Case Complexity:
1. O(n^2)
2. O(V + E) = O(n + intersection_count)Total: O(n^2)
My Best Case Optimization for Intersection Graph:
- engineer06 April 29, 2018 in United States
1. For each sensor, create two events for start and end of circles vertically. y = (y1 - r) and y = (y1 + r)
2. For each sensor, register those two events into an array.
3. Use a line sweep algorithm over 2, which is O(nlogn + intersection_count) and intersection_count may be n^2 at worst case.
I wonder if I should have had a better solution with the worst case < O(n^2).| Report Duplicate | Flag | PURGE
Amazon SDE-2 Algorithm - 0of 0 votes
AnswersNumbers with 4 are considered to be unlucky, floor numbers are skipped with numbers with 4; for a top level n, ask how many layers there are actually; for example n=20, that is 18 levels [Remove 4, 14]
- ajay.raj April 28, 2018 in United States| Report Duplicate | Flag | PURGE
Amazon Java Developer - 0of 0 votes
AnswersI read this question here in careercup and saw no comments on it. So, I am answering it.
- mohapatrasandeep60 April 24, 2018 in United States
given a string find the sum of number of unique substring characters.
means if string is ACAX. the sub strings are A,C,A,X,AC,CA,AX,ACA,CAX,ACAX. in ACA, A occurs more than once so, its count is not considered, but C occurs once so its count is 1. Similarly in ACAX, A's count=0,C's count=1,X's count=1. In such a manner find sum of all counts for all substrings. The worst case time complexityis O(n). IF same substring occurs more than once then find its sum for that many times.| Report Duplicate | Flag | PURGE
Amazon - 0of 0 votes
AnswersInput unsorted integer array represents a list of coins,
- ajay.raj April 18, 2018 in United States
find the minimum amount of money that cannot be formed by these coins, each coin can only be used once
E.g. {1,1} -> 3, {1,2,4} -> 8| Report Duplicate | Flag | PURGE
Amazon Java Developer - 0of 0 votes
AnswersGive me a list of int, find the length of the smallest cycle. For example, 1, 2, 1, 2, the length of the cycle is 2. Then 1, 2, 1, 2, 1 has a minimum length of 2. Then the length of 1, 2, 1, 2, 3 should be 5 because the entire list is not in repeat. Then the minimum length of 1, 2, 1, 2, 1, 1, 2 is 2.
- ajay.raj April 16, 2018 in United States| Report Duplicate | Flag | PURGE
Amazon Backend Developer - 0of 0 votes
AnswersFind the kth missing element in a sorted array. For example [2,3,5,7], k = 0: return 4, k = 1: return 6
- ajay.raj April 12, 2018 in United States
expected time complexity logn| Report Duplicate | Flag | PURGE
Amazon Backend Developer - 0of 0 votes
AnswersTo an array and K, each element in the array can only move K positions to the left at most, no limit to the right, try to sort the array under the limit of K
- ajay.raj April 10, 2018 in United States
a = [5, 2, 4, 3, 1], k = 2
Return [2, 3, 1, 4, 5]| Report Duplicate | Flag | PURGE
Amazon SDE1 - 0of 0 votes
AnswersGiven a function rand32() (random number range 0-2**32-1) that randomly generates a 32-bit int, design a new random function:
- ajay.raj April 09, 2018 in United States
Randn(n) generates a random distributed random number (0 - 2**n-1)
Rand3n(n) generates (0 - 3**n-1) the uniformly distributed random number| Report Duplicate | Flag | PURGE
Amazon SDE1 - 0of 0 votes
AnswerTopic: There is a set of coordinates. The original format of each coordinate is (1.3, 0.5). However, the comma and decimal point are gone. Only one string is left, allowing you to restore all possible combinations. For example, 123, possible (1, 23) (1, 2.3) (12, 3) (1.2, 3)
- ajay.raj April 09, 2018 in United States| Report Duplicate | Flag | PURGE
Amazon SDE1 - 0of 0 votes
Answersgiven period and threshold, Assume there is a endless streaming events, each event occurs at timestamp "x". The question want you to write an API that return true if number of the events are over the threshold within the period around timestamp "x"
- ajay.raj April 08, 2018 in United States
Ex:
period = 3, threshold =2
getEvent(10) -> false
getEvent(12) -> false
getEvent(13) -> true [10,12,13]
getEvent(20) -> false
part one: event come in order
part two: event come without order| Report Duplicate | Flag | PURGE
Amazon Software Developer - 0of 0 votes
AnswersGiven vector<int> nums, and pair<int, int> range. Find out how many continuous subsequences within this vector sum up the number within the range.
- ajay.raj April 08, 2018 in United States
Input: [1, 2, 3], [3,6]
Output: (4)
because [1,2,3], [1,2], [2,3], [3]| Report Duplicate | Flag | PURGE
Amazon Software Developer - 0of 0 votes
AnswerEach have a (x,y) coordinate.
- ajay.raj April 08, 2018 in United States
Write an API that group three Googler together for lunch if they are close enough. Otherwise, throw them in un-schedule pool.
Distance formula = sqrt((x1-x2) ^2 + (y1-y2) ^2)
Given an int range;
Range: 2
Input | Output of API Un-schedule pool
0,0 -> [] [[0,0]]
1,0 -> [] [[0,0], [1,0]]
3,0 -> [] [[0,0], [1,0], [3,0]]
1,1-> [[0,0], [1,0], [1,1]] [[3,0]]| Report Duplicate | Flag | PURGE
Amazon Software Developer - 0of 0 votes
AnswersGiven an vector<int> nums and an int target, you can change any element of the vector to positive or negative. How many uniquely different vector sum up to target?
- ajay.raj April 08, 2018 in United States
Input: [1,1,1], target = 2
[-1,1,1]
[1,-1,1]
[1,1,-1]
return (3)| Report Duplicate | Flag | PURGE
Amazon Software Developer - 0of 0 votes
Answerfind max path sum in DAG, weight can be negative
- ajay.raj April 06, 2018 in United States| Report Duplicate | Flag | PURGE
Amazon Software Engineer - 0of 0 votes
AnswersImplement a method to check if a n-ary tree is unival
- ajay.raj April 04, 2018 in United States
class TreeNode {
int val;
List<TreeNode> children;
TreeNode(int val) {
this.val = val;
children = new ArrayList<>();
}
}| Report Duplicate | Flag | PURGE
Amazon SDE1 - 0of 0 votes
AnswersGiven the length and width of a rectangle, how many ways can be used to go from the upper left corner to the upper right corner (each step can only go to the right, top right or bottom right):
- ajay.raj April 03, 2018 in United States
-follow up 1: If three points in the rectangle must be visited, how many ways
-follow up 2: If you are given an point H, and the path must go down below the H point, how to do it| Report Duplicate | Flag | PURGE
Amazon SDE1 - 0of 0 votes
AnswersThe thief has found himself a new place for his thievery again. There is only one entrance to this area, called the "root." Besides the root, each house has one and only one parent house. After a tour, the smart thief realized that "all houses in this place forms an n-nary tree". It will automatically contact the police if two directly-linked houses were broken into on the same night.
- ajay.raj March 31, 2018 in United States
Determine the maximum amount of money the thief can rob tonight without alerting the police.
/**
* Definition for a n-ary tree node.
* public class TreeNode {
* int val;
* List<TreeNode> kids;
* }
*/
class Solution {
public int rob(TreeNode root) {
}
}| Report Duplicate | Flag | PURGE
Amazon SDE1 - 1of 1 vote
AnswerFor two string a, b, their distance is defined as the number of positions at which the corresponding character are different.
- ajay.raj March 31, 2018 in United States
Now you can swap characters at any two locations once, and ask how to swap to make the distance the smallest.| Report Duplicate | Flag | PURGE
Amazon Backend Developer - 0of 0 votes
Answerspreorder Traversing a n-ary tree without using recurrsion
- ajay.raj March 31, 2018 in United States
TreeNode<T> {
T val;
List<TreeNode> children;
}| Report Duplicate | Flag | PURGE
Amazon SDE1 - 0of 0 votes
AnswersGiven two methods for the person class, one to find a dad and one to find a mother, using these two methods to achieve a method to determine whether the two people are related to blood, assuming a limited number of people.
- ajay.raj March 30, 2018 in United States| Report Duplicate | Flag | PURGE
Amazon SDE1 - 0of 0 votes
AnswersSelf-implemented data structures and methods, output all the heirs. To achieve birth (parent, name), dead (name), getAllSucession (). There is a king, you can use birth plus children, dead dead. The order of inheritance is the same as preorder except that this tree has multiple children.
- ajay.raj March 30, 2018 in United States| Report Duplicate | Flag | PURGE
Amazon SDE1 - 0of 0 votes
AnswersGiven an Input file of IPv4 addresses, filter and write them into Valid and Invalid IPs.
- pragramticProgrammer March 28, 2018 in United States
Input file = ["192.100.0.1, "10.0.0.1", "aa.bb.cc.dd", "10.0", "999.10.10.1"]
Valid = []
Invalid = []| Report Duplicate | Flag | PURGE
Amazon Software Engineer - 0of 0 votes
AnswerA coffee machine has three buttons (S, M, L). After pressing each button, the coffee machine will flow out of a range of coffee [s1, s2], [m1, m2], [l1, l2], but the outflow of coffee The amount is random. There is a cup with a total capacity of c2. There is a tick c1 on the cup. If the amount of coffee is [c1, c2], it is considered full.
- ajay.raj March 28, 2018 in United States
After asking for a series of button operations, can the coffee be filled in [c1, c2] but not overflow?| Report Duplicate | Flag | PURGE
Amazon Backend Developer - 0of 0 votes
AnswersInput like method stack trace: "main, start", "foo, start", foo, end", "bar, start", "bar end", "main, end", "main2, start", "main2, end"
Output String, such as the following format, to indicate the order in which the method was called and the hierarchy
- ajay.raj March 28, 2018 in United Statesmain Foo Bar main2
| Report Duplicate | Flag | PURGE
Amazon Backend Developer - 0of 0 votes
Answerspublic TreeNode{
int val = val;
TreeNode left, right;
public TreeNode(int val){
this.val = val;
}
given a tree and an API, delete a part of the nodes in the tree and return the forest formed after the node is deleted.
public List<TreeNode> deletenodes(TreeNode root, List<TreeNode> toDeletes){
}
example
- ajay.raj March 28, 2018 in United States1 / \ 2 3 / / \ 4 5 6 If you delete the 2 and 5 nodes, you will need to return to the forest [4, 1] \ 3 \ 6
| Report Duplicate | Flag | PURGE
Amazon Java Developer - 0of 0 votes
Answersturns the following format string into a tree: node has keys, values, and subtrees.
- ajay.raj March 23, 2018 in United States
For example, the first key is node1 and the value is ‘aaaa’
<node1>aaaaa<node2>bbbbb</node2><node3>cccc</node3><node4>dddd</node4></node1>| Report Duplicate | Flag | PURGE
Amazon Backend Developer - 0of 0 votes
Answersfind longest common suffix of two linked list.
- ajay.raj March 18, 2018 in United States| Report Duplicate | Flag | PURGE
Amazon Backend Developer - 0of 0 votes
AnswersGive a 0/1 matrix to find and remove the islands. Assume that the boundaries of the matrix are 1
- ajay.raj March 15, 2018 in United States
The definition of islands is surrounded by 0
The simplest example is
enter:
111111
100001
100101
100001
111111
Output:
111111
100001
100001
100001
111111| Report Duplicate | Flag | PURGE
Amazon Backend Developer - 0of 0 votes
AnswersWrite a hash function so that a string and its reverse get the same return value
- ajay.raj March 15, 2018 in United States
Hash(‘banana’) == hash(‘ananab’)
Hash(‘banana’) == hash(‘banana’)
Hash(‘banana’) != hash(‘banaaa’)| Report Duplicate | Flag | PURGE
Amazon Backend Developer