Google Interview Question for Software Engineers


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Comment hidden because of low score. Click to expand.
1
of 1 vote

def get_increasing_list(l, n):
    q = [0, 1, 2]
    print l[:n]
    k = len(l)
    visited = []
    while len(q) != 0:
        num = q.pop()
        for i in range(num+1, k):
            q.append(i)
            if len(q) >= n and q[:n] not in visited:
                res = map(lambda x: l[x], q)
                print res
                visited.append(q[:n])

- Anonymous July 30, 2019 | Flag Reply
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0
of 0 votes

q = list(range(n))

for any n. The above code code works well for only n=3.

- sleebapaul January 31, 2020 | Flag
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0
of 0 vote

vector<int> GetRandomSublist(vector<int> A, int n)
{
	default_random_engine seed((random_device())());

	if (n < 0 || n >= A.size()) return {};

	for (int i = 0; i < n; i++)
	{
		uniform_int_distribution<int> rand_gen(i, A.size() - 1);
		int num = rand_gen(seed);
		swap(A[i], A[num]);
	}

	vector<int> ret;
	for (int i = 0; i < n; i++)
		ret.emplace_back(A[i]);
	sort(ret.begin(), ret.end());

	return ret;

}

- LANorth July 06, 2019 | Flag Reply
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0
of 0 vote

public static int[] getSubArray(int [] array, int n){
Random random = new Random();
int[] result = new int[n];
int index = 0;
for(int i = 0;i<n;i++){
index = random.nextInt((array.length-n+i-index)+1)+index;
result[i]=array[index++];
}
return result;
}

- Anonymous July 17, 2019 | Flag Reply
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0
of 0 vote

public static int[] getSubArray(int [] array, int n){
    Random random = new Random();
    int[] result = new int[n];
    int index = 0;
    for(int i = 0;i<n;i++){
      index = random.nextInt((array.length-n+i-index)+1)+index;
      result[i]=array[index++];
    }
    return result;
  }

- doesntmatter July 17, 2019 | Flag Reply
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0
of 0 vote

def get_increasing_list(l, n):
q = [0, 1, 2]
print l[:n]
k = len(l)
visited = []
while len(q) != 0:
num = q.pop()
for i in range(num+1, k):
q.append(i)
if len(q) >= n and q[:n] not in visited:
res = map(lambda x: l[x], q)
print res
visited.append(q[:n])

- Anonymous July 30, 2019 | Flag Reply
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0
of 0 vote

def get_perm(nums, k):
    if k == 1 :
        for n in nums:
            yield [n]
    else:
        for i,n in enumerate(nums):
            for x in get_perm(nums[i+1:],k-1):
                yield [n] + x

def main(nums,k):
    if len(nums) < k:
        return []
    return list(get_perm(nums,k))

main([1,2,3,4,5], 3)

- python August 10, 2019 | Flag Reply
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0
of 0 vote

//make the ans, temp vector in main. v is the given vector
void func(vector<int> &temp, vector<int> v, int i, int m, vector<vector<int> > &ans) {
if(temp.size() == m) {
ans.emplace_back(temp);
return;
}
for(int j = i; j < v.size(); j++) {
temp.push_back(v[j]);
func(temp, v, j + 1, m, ans);
temp.pop_back();
}
}

- Aheli Ghosh August 11, 2019 | Flag Reply
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0
of 0 vote

void func(vector<int> &temp, vector<int> v, int i, int m, vector<vector<int> > &ans){
if(temp.size() == m){
ans.emplace_back(temp);
return;
}
for(int j = i; j < 5; j++){
temp.push_back(v[j]);
func(temp, v, j + 1, m, ans);
temp.pop_back();
}
}

- Aheli Ghosh August 11, 2019 | Flag Reply
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0
of 0 vote

import random

def GetSubArray(a, n):
    diff_n = len(a) - n
    
    if diff_n < 0:
        return []
    
    if diff_n == 0:
        return a
        
    index = 0
    result = []
    for i in range(0, n):
        index = random.randint(index, diff_n + i)
        result.append(a[index])
        index = index + 1
    return result

- Anonymous February 23, 2020 | Flag Reply
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0
of 0 votes

The numbers don't all have an equal chance of getting in the subset.

- yehadut April 26, 2020 | Flag
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0
of 0 vote

import random

def GetSubArray(a, n):
    diff_n = len(a) - n
    
    if diff_n < 0:
        return []
    
    if diff_n == 0:
        return a
        
    index = 0
    result = []
    for i in range(0, n):
        index = random.randint(index, diff_n + i)
        result.append(a[index])
        index = index + 1
    return result

- Rachel February 23, 2020 | Flag Reply
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0
of 0 vote

let ran = (set, size) => {
    // if the size is greater than the range, theres nothing to see here
    if (size >= set.length) {
        return -1
    }
    const output = new Map();

    // since the input is sorted, the first number will be the smallest
    const [smallest] = set

    // formula for determining the start rang
    const range = (set.length - size) + 1;
    const start = randomHelper(smallest,range);

    // this will be our first number in the result set
    output.set(start, true)

    while (output.size < size) {
        // get the next random number in the range
        let nextRan = randomHelper(start, set.length)
        
        // if it hasn't been included, go for it
        if (!output.has(nextRan)) {
            output.set(nextRan, true)
        }
    }
    // return sorted set
    return [...output.keys()].sort((a,b) => a -b);
}

function randomHelper(start, end) {
    return Math.round(Math.random() * (end - start) + start)
}

- Jason March 28, 2020 | Flag Reply
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0
of 0 vote

let ran = (set, size) => {
    // if the size is greater than the range, there's nothing to see here
    if (size >= set.length) {
        return -1
    }
    const output = new Map();

    // since the input is sorted, the first number will be the smallest
    const [smallest] = set

    // formula for determining the start rang
    const range = (set.length - size) + 1;
    const start = randomHelper(smallest,range);

    // this will be our first number in the result set
    output.set(start, true)

    while (output.size < size) {
        // get the next random number in the range
        let nextRan = randomHelper(start, set.length)
        
        // if it hasn't been included, go for it
        if (!output.has(nextRan)) {
            output.set(nextRan, true)
        }
    }
    // return sorted set
    return [...output.keys()].sort((a,b) => a -b);
}

function randomHelper(start, end) {
    return Math.round(Math.random() * (end - start) + start)
}

- Jmatthews@netprotocal.com March 28, 2020 | Flag Reply
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0
of 0 vote

Knuth shuffle then order by original list. O(n + len(L))

import random
from copy import copy

def random_subset(original_list, n):
  L = copy(original_list)
  // Differentiate items which have the same value by adding a second "count" int
  for i, val in enumerate(L):
    if i == 0:
      L[i] = (val, 1)
    else:
      prev_val, prev_count = L[i-1]
      L[i] = (val, prev_count + 1) if val == prev_val else (val, 1)

  // Hash each value to its index, so that we maintain the order at the end
  val2i = {val: i for i, val in enumerate(L)}

  // Choose items randomly, and move them to the end of the list so they don't get chosen twice.
  for i in range(n):
    rand_i = random.randint(0, len(L)-1-i)
    L[rand_i], L[len(L)-1-i] = L[len(L)-1-i], L[rand_i]

  // bucket sort the randomly selected items, now at the end of our list
  bucket = [False] * len(L)
  for val in L[len(L)-n:]:
    bucket[val2i[val]] = True
  subset = []
  for i, inSubset in enumerate(bucket):
    if inSubset:
      subset.append(original_list[i])
  return subset

- yehadut April 26, 2020 | Flag Reply
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0
of 0 vote

package T11;

import java.util.ArrayList;
import java.util.Stack;

public class T11 {
	
	static int[] L = { 1, 2, 3, 4, 5};
	static int N = 3;
	static ArrayList<Integer> input = new ArrayList<>();
	static ArrayList<Object[]> output = new ArrayList<>();
	static Stack<Integer> process = new Stack<>();

	public static void main(String[] args) {

		init();
		process();
		
		// find out the result
		for(Object[] temp : output) {
			System.out.print("[");
			for(int i = 0 ; i < temp.length; i++) {
				String t = temp[i].toString();
				if(i != temp.length-1)
					System.out.print(Integer.valueOf(t)+", ");
				else
					System.out.print(Integer.valueOf(t));
			}
			System.out.println("]");
		}

	}

	private static void init() {

		for (int i = 0; i < L.length; i++) {
			input.add(L[i]);
		}

//		System.out.println(input);
	}

	private static void process() {

		for (int i = 0; i < input.size() - N + 1; i++) {
			process.removeAllElements();
			process.push(input.get(i));
			oneScan(i, i, false);
		}
	}

	private static void oneScan(int index, int secondIndex, boolean last) {

		int getIndex = index;
		int getSecondIndex = secondIndex;

		if (process.size() > 1) {
			process.pop();
		}

		if (last == true)
			return;

		Object[] temp = null;

		for (int i = index; i < input.size(); i++) {

			if (process.size() == N) {
				if (process.size() < N)
					continue;

				temp = (Object[]) process.toArray();


				if(checkDup(temp) == true) continue;
				output.add(temp);

				process.pop();
				getSecondIndex = findIndex(process.peek());
				i--;
				continue;

			} else {
				if (input.get(i) == input.get(getSecondIndex))
					continue;

				if (process.peek() >= input.get(i)) {
					continue;
				} else {
					process.push(input.get(i));
				}
			}
		} // end of for i

		if (process.size() == N) {
			temp = (Object[]) process.toArray();

			if(checkDup(temp) == false) {
				output.add(temp);
				process.pop();
				getSecondIndex = findIndex(process.peek());
			}
		}

		getIndex = getIndex + 1;
		if (getIndex == input.size())
			oneScan(getIndex, getSecondIndex, true);
		else
			oneScan(getIndex, getSecondIndex, false);

	}

	private static int findIndex(int value) {
		int retVal = 0;

		for (int i = 0; i < input.size(); i++) {
			if (value == input.get(i)) {
				retVal = i;
				break;
			}
		}
		return retVal;
	}
	
	private static boolean checkDup(Object[] toCompare) {
		boolean retVal = false;
		
		for(Object[] getOutput : output) {
			
			for(int i = 0 ; i < getOutput.length; i++) {
				String getEachElement = getOutput[i].toString();
				if(getEachElement.equalsIgnoreCase(toCompare[i].toString())) {
					retVal = true;
				}else {
					retVal = false;
					break;
				}
			}
			if(retVal == true) return retVal;
		}
		
		return retVal;
	}


}

- mannerh1 May 12, 2020 | Flag Reply
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0
of 0 vote

public static List<Integer> sublist(final List<Integer> nums, final int size){
        if(size == nums.size()) return nums;
        else if( size == 0) return Collections.emptyList();
        else if (size == 1) return Arrays.asList(nums.get(new Random().nextInt(nums.size())));

        final List<Integer> sublist = new LinkedList<>();
        final Random rand = new Random();

        int selectIndex = -1;

        while (sublist.size() < size){
            int randomDelta = 0;

            final int itemsRemaining = size - sublist.size();
            final int lowestPos = nums.size() - itemsRemaining;

            while (randomDelta == 0 || selectIndex + randomDelta > lowestPos)
                randomDelta = rand.nextInt(nums.size() - selectIndex);

            selectIndex += randomDelta;
            sublist.add(nums.get(selectIndex));
        }

        return sublist;
    }

- Yev August 30, 2020 | Flag Reply
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0
of 0 vote

import itertools
ll=[1,2,3,4,5]
n=3
mlist=n*[ll]
combinations = list(itertools.product(*mlist))
for value in combinations:
  if(len(set(value)) == len(value) and list(value) == sorted(value)):
      print(value)

It also takes care of condition with one of the element being zero. try with [1,2,3,4,0]

- Sanjay May 11, 2021 | Flag Reply
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0
of 0 vote

import itertools
ll=[1,2,3,4,5]
n=3
mlist=n*[ll]
combinations = list(itertools.product(*mlist))
for value in combinations:
  if(len(set(value)) == len(value) and list(value) == sorted(value)):
      print(value)

Above works fine with empty array [] and also if one of the elements is zero [1,2,3,4,0]

- Sanjay May 11, 2021 | Flag Reply
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0
of 0 vote

import random

def random_sublist(n,k):
sublist=[]
offset=0
var = k
while var > 0 :
ind = random.randint(1,n-var-offset+1)+offset
sublist.append(ind)
offset=ind
var=var-1
return sublist

- Snigdha Chandan Khilar May 15, 2021 | Flag Reply
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0
of 0 vote

This is my solution with recursion. It works with any arrays and any N

mport java.util.ArrayList;
import java.util.List;

public class Main {
public static void main(String[] args) {

fun(7,new ArrayList<Integer>(), 0,3);

}


static void fun(int size, List<Integer> result, int i, int n) {
if(result.size() >= n)
printResult(result);
else {
findValue(size, result, i, n, i+1);
}

}

static void findValue(int size, List<Integer> result, int i, int n,int j) {
if(j <= size -n +i +1) {
List<Integer> newResult = new ArrayList<Integer>(result);
newResult.add(j);
fun(size, newResult, i+1, n);
findValue(size, result, i, n,j+1);
}
}
static void printResult(List<Integer> result) {
for(Integer value: result) {
System.out.print(value+ " ");
}
System.out.println();
}


}

- Liliana June 01, 2021 | Flag Reply
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0
of 0 vote

#include <vector>

void generate(vector<int> & arr, int k, vector<vector<int>> & result, vector<int> & current, int index = 0){
    int n = arr.size();
    
    if(current.size() == k){
        result.push_back(current);
        return;
    }
    
    for(int i=index; i<n; i++){
        current.push_back(arr[i]);
        generate(arr, k, result, current, i+1);
        current.pop_back();
    }
}

vector<vector<int>> getAllCombinations(vector<int> arr, int k){
    vector<vector<int>> result;
    vector<int> current = {};
    generate(arr, k, result, current);
    return result;
}

void printResult(vector<vector<int>> matrix){
    int n = matrix.size();
    int m = matrix[0].size();
    for(int i=0; i<n; i++){
        for(int j=0; j<m; j++){
            cout << matrix[i][j] << " ";
        }
        cout << endl;
    }
}

int main() {
    vector<int> arr = {1,2,3,4,5};
    printResult(getAllCombinations(arr, 4));
}

- Anonymous September 12, 2021 | Flag Reply
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0
of 0 vote

Easy backtracking based solution c++

#include <iostream>
#include <vector>

using namespace std;

void generate(vector<int> & arr, int k, vector<vector<int>> & result, vector<int> & current, int index = 0){
    int n = arr.size();
    
    if(current.size() == k){
        result.push_back(current);
        return;
    }
    
    for(int i=index; i<n; i++){
        current.push_back(arr[i]);
        generate(arr, k, result, current, i+1);
        current.pop_back();
    }
}

vector<vector<int>> getAllCombinations(vector<int> arr, int k){
    vector<vector<int>> result;
    vector<int> current = {};
    generate(arr, k, result, current);
    return result;
}

void printResult(vector<vector<int>> matrix){
    int n = matrix.size();
    int m = matrix[0].size();
    for(int i=0; i<n; i++){
        for(int j=0; j<m; j++){
            cout << matrix[i][j] << " ";
        }
        cout << endl;
    }
}

int main() {
    vector<int> arr = {1,2,3,4,5};
    printResult(getAllCombinations(arr, 4));
}

- Anil Pal September 12, 2021 | Flag Reply
Comment hidden because of low score. Click to expand.
-1
of 1 vote

import random
def generate_n_list(lst, n):
    if n > len(lst):
        return []
    if n == len(lst):
        return lst
    res = []

    for i in range(len(lst) - 1,-1,-1):
        j = random.randrange(0,i + 1,1)
        temp = lst[j]
        lst[j] = lst[i]
        lst[i] = temp
        res.append(temp)

        if len(res) == n:
            break

    return sorted(res)

- jeff July 04, 2019 | Flag Reply
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0
of 0 votes

it seems to not respect the requirements: this solution allows to have descending order

- lulu September 09, 2019 | Flag
Comment hidden because of low score. Click to expand.
-1
of 1 vote

public void sublist(int[] L, int n) {
for (int i=0; i <5; i++){
for (int j=i+1; j < 5; j++ ){
for (int k=j+1; k < 5; k++){
if (L[i] <L[j] && L[j]<L[k]){
System.out.println(L[i] +"," + L[j] + " ," + L[k] + "");
}
}
}
}
}

- Anonymous July 05, 2019 | Flag Reply
Comment hidden because of low score. Click to expand.
-1
of 1 vote

public void sublist(int[] L, int n) {
for (int i=0; i <5; i++){
for (int j=i+1; j < 5; j++ ){
for (int k=j+1; k < 5; k++){
if (L[i] <L[j] && L[j]<L[k]){
System.out.println(L[i] +"," + L[j] + " ," + L[k] + "");
}
}
}
}
}

- code gru July 05, 2019 | Flag Reply
Comment hidden because of low score. Click to expand.
-2
of 2 vote

{
my name is varma
}

- Anonymous August 10, 2019 | Flag Reply


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