Describe how you could use a single array to implement three stacks..Optimize SOlution Needed

Approach 1:

Divide the array in three equal parts and allow the individual stack to grow in that limited space (note: “[“ means inclusive, while “(“ means exclusive of the end point).
»»for stack 1, we will use [0, n/3)
»»for stack 2, we will use [n/3, 2n/3)
»»for stack 3, we will use [2n/3, n)
This solution is based on the assumption that we do not have any extra information about the usage of space by individual stacks and that we can’t either modify or use any


Approach 2:
In this approach, any stack can grow as long as there is any free space in the array.
We sequentially allocate space to the stacks and we link new blocks to the previous block. This means any new element in a stack keeps a pointer to the previous top element of that particular stack.
In this implementation, we face a problem of unused space. For example, if a stack deletes some of its elements, the deleted elements may not necessarily appear at the end of the array.
So, in that case, we would not be able to use those newly freed spaces.
To overcome this deficiency, we can maintain a free list and the whole array space would be given initially to the free list. For every insertion, we would delete an entry from the free list. In case of deletion, we would simply add the index of the free cell to the free list.
In this implementation we would be able to have flexibility in terms of variable space utilization
but we would need to increase the space complexity.

Wap to Replace all the instances of ’%’ with this string s,offered that the length of the array

Given an array of dimension n with very first l positions crammed with characters and a string s ,replace all the instances of ’%’ with this string s,offered that the length of the array is enough to deal with these substitutions.

input output

eg: abcdef%ghi%—— and “ppp” abcdefpppghippp



Although program is Simple but i am posting here as i found on one forum that it is asked by MS:)

Data Structure:Array

Algorithm:
1.count number of % character
2.increase size of array by lenth + 2* number op & chars.
3. scan through new array & replace all % occurance with "ppp"


class test
{
public static void ReplaceFun(char[] str, int length) {
int percentCount= 0, newLength, i = 0;
for (i = 0; i < length; i++)
{
         if (str[i] == '%')
        {
            percentCount++;
        }
}

newLength = length + percentCount* 2; str[newLength] = '\0';

for (i = length - 1; i >= 0; i--)
{
if (str[i] == '%')
{
str[newLength - 1] = 'p';
str[newLength - 2] = 'p';
str[newLength - 3] = 'p';
newLength = newLength - 3;
}
else
{
str[newLength - 1] = str[i];
newLength = newLength - 1;
}

}
System.out.println(str);
}
public static void main(String a[])
{
ReplaceFun(new char[]{'s','h','%','a','%','%','s','h','a','n','%','%','%','k'},15);

}
}

WAP to Create New Arrayfrom Given Array Suuch That array2[i] will hold the value of the left-most integer from the range array1[i+1] to array1[n-1] such that it is greater than array1[i]. If no such element exists, assign -1.

You are given an array of integers, say array1 of size n. You have to create another array (say array2) and fill its contents by following this rule: array2[i] will hold the value of the left-most integer from the range array1[i+1] to array1[n-1] such that it is greater than array1[i]. If no such element exists, assign -1.

Example ar[]={4,5,2,25}
4 --> 5
5 --> 25
2 --> 25
25 --> -1
arr[]=1 21 8 11 13 9 6
1- 21
21- -1
8 11
11 13
13 -1
9 -1
6 -1

Data Structure:

Algorithm:


Time Complexity O(N^2)
Space Complexity O(1)
Run here

Optimize Approach



Time Complexity O(N)
Space Complexity O(N) Stack Space
Run here

Detect 1% Duplicate Entry in a File of 13 Million Entries Efficiently.

We have a text file with 13 Million entries, all numbers in the range from 1.000.000 to 100.000.000. Each line has only one number. The file is unordered and we have about 1% duplicate entries. Remove the duplicates.

As We have a Huge Data obvious things that should come into mind is using bit array or bit set where ith bit represent the position of number in array of size 13* 2^20

before start solving question i suggest you people to check basics of bit operations here

#include
#include
using namespace std;
int main()
{
int i=0,j=0,k=0;
int n=18;
n|=1<<3;//Set the ith bit here i=3
printf( " %d ", n);
n&=~(1<<3);//clear ith bit
printf( " %d ", n);
n^=1<<1;//toggle ith bit
printf( " %d ", n);
i=n&(1<<4)?1:0;//check ith (i=4)bit set or not
printf( " %d ", i);
return 0;
}


Data Structure:Bit Array

Algorithm:
1.set ith bit n bit arry when reading number 1 by one from file .
2.if ith bit corrosponding to number is already set then number is duplicate .
& we are done.

as we are using bit array here so When using an array of bytes to represent set of bits, i.e., a bit array or bitset, the index of the byte in the array associated with a bit n can be calculated using division:

ith index / CHAR_BIT (number represented by 32 bit or 64 bit etc)

where n is the index of the given bit and CHAR_BIT gives the number of bits in a C char.

"this will give position of byte element in array elements"

The index of the bit within the byte indexed by the above can be calculated via a modulo operation:

n % CHAR_BIT

"so this will give us position of bit inside byte."

so then we can write the following method to find 1% duplicates

bool setBit(int a[], int i)
{
int index = i / 8; //position number in array
int offset = i % 8;//position of bit in byte
if (a[index] & (1<< offset))//check bit is set or not
return false;//when ith bit is already set
a[index] |= 1< return true;
}

Time Complexity O(N) size of file
Feel Free to Comment or Optmize the Solution

Given a 1D Array (linear) , you have to convert it in to 2D array & then find sum of each column.you have given number of rows K & number of elemnets N in array.

You are given a 1D array of integers, such as: int[] array = [3,4,7,2,2,6,0,9];
Suppose you need to treat this array as a 2D table with a given number of rows.
You want to sum the columns of the table.One value of numRows is 4..in that case the resultant array would look like

what if numRows==4?
3 4
7 2
2 6
0 9
—-
12 21

Data Structure : 2D Array


Algorithm:
1.As we have given Number of elements N in array & number of rows k to make 2D
Array we can easily find out number of column C=N/k
2.Then using two for loop down the 2D array 1st loop run for coumns & inner loop
work for rows.(A Tricky Mind Needed here although so Simple

).as in inner loop
we will increment by value of column we get.

Working Code:

#include
#include
using namespace std;
int main()
{
int i=0,j=0,k=0,sum=0;
int r=3;//row
int a[]={3,4,7,2,2,6,0,9,5,8,11};
int n=sizeof(a)/sizeof(int);
j=n/r;//column

while(k {
for(i=k;i {
sum=sum+a[i];
}
cout< sum=0;
k++;
}

return 0;
}

Time Complexity O(column*row)=O(N) see above relation C=N/r
Space Complexity O(1)
Run Here https://ideone.com/RWjEf

Given ‘n’ no of sets and each set is of a variable size. Find out the cross product of these ‘n’ of sets.

For eg. {1,2} , {3,4} , {5,6,7} these are the three sets.The cross product of these sets would be as below.
{1,3,5},{1,3,6},{1,3,7},{1,4,5},{1,4,6},{1,4,7},{2,3,5},{2,3,6},{2,3,7},{2,4,5},
{2,4,6},{2,4,7}.


Data Structure: Binary Tree

Algorithm:


Working Code:






Time Complexity
Space Complexity
Run Here

Given an array of integers, find out number of ways in which you can select increasing subsequences of length k(k<=n).

eg array is 1 4 6 2 5 & k=3
Output: 3
Sequences: 1 4 6, 1 4 5, 1 2 5


Question is a variant of longest increasing sub sequence problem(LIS Problem) or longest consecutive elements

See http://en.wikipedia.org/wiki/Longest_increasing_subsequence

Data Structure: Array
Algorithm:LIS


Working Code:By Manu

import java.io.*

class LISOfLengthK
{

private static void lisOfLengthK(Integer [] inputArray, int k) {
int n = inputArray.length, temp, count;
Integer [] best = new Integer[n];
Integer [] last = new Integer[n];
Integer [] outputArray = new Integer[k];
for(int i=0;i inputArray[i]) {
best[j] = best[i]+1;
last[j] = i;
if(best[j] == k) {
temp = j;
count =0;
outputArray[count++] = inputArray[temp];
while(last[temp] != -1) {
outputArray[count++] = inputArray[last[temp]];
temp = last[temp];
}
for(int index=k-1;index>=0;index--)
System.out.print(outputArray[index] + " ");
System.out.println();
}
}
}
}
}

public static void main(String[] args) throws NumberFormatException, IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
int n = Integer.parseInt(br.readLine());
Integer [] inputArray = new Integer[n];
for(int i=0;i inputArray[i] = Integer.parseInt(br.readLine());
int k = Integer.parseInt(br.readLine());
lisOfGivenLength(inputArray, k);
}

}


Time Complexity O(N^2)
Space Complexity O(1)
https://ideone.com/Jbtw0

WAP Convert Set of Nodes of Binary Tree where each node contains two value i, j & i value follow BST property , j value follow Heap Property, Build BST form these Nodes.

A rooted binary tree with keys in its nodes has the binary search tree
property (BST property) if, for every node, the keys in its left
subtree are smaller than its own key, and the keys in its right
subtree are larger than its own key. It has the heap property if, for
every node, the keys of its children are all smaller than its own key.
You are given a set of n binary tree nodes that each contain an
integer i and an integer j. No two i values are equal and no two j
values are equal. We must assemble the nodes into a single binary tree
where the i values obey the BST property and the j values obey the
heap property. If you pay attention only to the second key in each
node, the tree looks like a heap, and if you pay attention only to the
first key in each node, it looks like a binary search tree.Describe a
recursive algorithm for assembling such a tree

Indirectly They Asked to Implement Treap

Data Structure: Treap( Heap + Binary Search Tree)

Algorithm:
1.Sort the nodes in decreasing order of their j values and then simply build the
2.BST according to the i values starting from the first node in the obtained sorted
list. The first node will be the root. For example, let the given nodes (i,j
pairs) be:

so our structure of node will looks like this

struct node
{
int i;
int j;
struct node *left;
struct node *right;
};



For Example:
(12,6) (18,25) (19,10) (17,5) (19,10) i.e. 5 nodes
nodes after sorting in decreasing order according to j values:
(18,25) (16,11) (19,10) (12,6) (17,5)
So the tree would be something like this:


(18,25)
|
| |
(16,11) (19,10)
|
| |
(12,6) (17,5)


Working Code:


#include
#include



struct node
{
int i;
int j;
struct node *left;
struct node *right;
};


void mySwap(struct node **n1, struct node **n2)
{
struct node *tmp;
tmp = *n1;
*n1 = *n2;
*n2 = tmp;
}


struct node *myInsert(struct node *root, struct node *nodeToInsert)
{
if(root == NULL)
{
return nodeToInsert;
}
else
{
if(nodeToInsert->i <= root->i)
{
root->left = myInsert(root->left,nodeToInsert);
}
else
{
root->right = myInsert(root->right,nodeToInsert);
}
return root;
}
}


void myFunc(struct node *arr[], struct node **resultTree, int size)
{
if(!size)
return;
int ind;
int maxInd = 0;
for(ind=0;indj > arr[maxInd]->j)
maxInd = ind;
*resultTree = myInsert(*resultTree,arr[maxInd]);//inserting node with maximum j value
mySwap(&arr[maxInd],&arr[size-1]);
myFunc(arr,resultTree,size-1);
}


int main()
{
int n;
struct node *arr[100];
scanf("%d",&n);
int ind;
int ival,jval;
struct node *result = NULL;
for(ind=0;indi = ival;
arr[ind]->j = jval;
arr[ind]->left = NULL;
arr[ind]->right = NULL;
}
myFunc(arr,&result,n);
//levelOrderTraversal(result);
//PreOrderTraversal(result);
for(ind=0;ind free(arr[ind]);
return 0;
}

Solution Given BY Vipul

Time Complexity O(N^2)
Space Complexity O(logn)
Run Here https://ideone.com/o7dfU

WAP to Find Two Leaf Nodes in Binary Tree such that F(x,y) is maximum

Given a binary tree, find 2 leaf nodes say X and Y such that F(X,Y) is maximum where F(X,Y) = sum of nodes in the path from root to X + sum of nodes in the path from root to Y - sum of nodes in the common path from root to first common ancestor of the Nodes X and Y


Data Structure: Binary Tree

Algorithm:


Working Code:




Time Complexity
Space Complexity

WAP to Find Number of Pairs of Intersecting Disc ,Given Array of N Integers .

Given an array A of N integers we draw N discs in a 2D plane, such that i-th disc has center in (0,i) and a radius A[i]. We say that k-th disc and j-th disc intersect, if k! =j and k-th and j-th discs have at least one common point.

Write a function

class Solution { public int number_of_disc_intersections(int[] A); }

which given an array A describing N discs as explained above, returns the number of pairs of intersecting discs. For example, given N=6 and

A[0]=1 A[1]=5 A[2]=2 A[3]=1 A[4]=4 A[5]=0

there are 11 pairs of intersecting discs:

0th and 1st
0th and 2nd
0th and 4th
1st and 2nd
1st and 3rd
1st and 4th
1st and 5th
2nd and 3rd
2nd and 4th
3rd and 4th
4th and 5th

so the function should return 11.

The function should return -1 if the number of intersecting pairs exceeds 10,000,000. The function may assume that N does not exceed 10,000,000

Hint & Algorithms: Use HashTable , Linear Probing Based, in Case of Collision increment Corresponding Counter,if i am correct ,coding part is very easy, still if get time, will surely put running code here as usual :) Happy Coding

Time Complexity O(N) Where N is Size of Array
Space Complexity O(N)