DEV Community: Ganesh K S

Length of consecutive 1's in Binary representation

Ganesh K S — Wed, 15 May 2024 02:21:21 +0000

let input=110

output=3

In order to do this first we need to check whether the binary form of input contains consecutive or not

n is given input if we do binary and operation between n left shift by 1 the output if it comes non zero then it is having consecutive 1

In order to find the longest consecutive ones in binary representation

first step - n & n<<1 if it comes non zero then increment the initialized variable count to 1

second step - if non zero number comes up then previous output will become n and again continue step until n equals to zero

function getLongestConsecutiveOnes(n){
  let count=0

  while(n > 0){
    count++;
    n=(n&(n<<1))
  }

   return count;
}

console.log(getLongestConsecutiveOnes(110))

Left Rotate array by K elements using reverse approach

Ganesh K S — Sun, 21 Apr 2024 12:03:37 +0000

Given array

const arr=[1,2,3,4,5,6]

Left Rotate array by 2 elements , Output will be ---

arr = [3,4,5,6,1,2]

This problem can be solve with reverse array approach easily

First devide the array with given K elements to rotate
In our case K is 2

Reverse the corresponding devision of elements
So after reversing the array will be

Now reverse the whole array that will give you the output
After reversing whole array the output will be

Implementation in Code level

let arr=[1,2,3,4,5,6]
let k=2

function reverseArray(arr,start,end){
    while(start<end){
        [arr[start],arr[end]]=[arr[end],arr[start]];
        start++;
        end--;
    }

    return arr;
}

//this will be the first step to reverse the first half
let reversedFirstHalf=reverseArray(arr,0,k-1)

//this will be the second step to reverse the second half
let reversedSecondHalf=reverseArray(reversedFirstHalf,k,arr.length-1)

//After reversing the whole array
let rotateArrayOutput = reverseArray(reversedSecondHalf,0,arr.length-1)

Second Largest Element in an array

Ganesh K S — Sun, 21 Apr 2024 08:04:05 +0000

This is the given array

let arr=[1,2,4,7,7,5]

Declare the two variables

let firstMax;
let secondMax;

Then find out the which is greater in the first 2 index values

if(arr[0] > arr[1]){
  firstMax = arr[0]
}else{
  secondMax=arr[1]
}

if(arr[1] > arr[0]){
  firstMax = arr[1]
}else{
  secondMax=arr[0]
}

Then begin the loop from 2 to last index of the array

In the first loop

In the second loop

In the third loop

In the fourth loop

Complete solution to find the second largest in the array

let arr=[1,2,4,7,7,5]

let firstMax;
let secondMax;

if(arr[0] > arr[1]){
  firstMax = arr[0]
}else{
  secondMax=arr[1]
}

if(arr[1] > arr[0]){
  firstMax = arr[1]
}else{
  secondMax=arr[0]
}

for(let i=2;i<arr.length;i++){
  if(arr[i] > firstMax){
    secondMax=firstMax;
    firstMax=arr[i];
  }

  if(arr[i] > secondMax && arr[i] < firstMax){
    secondMax = arr[i]
  }

}

console.log("firstMax",firstMax)
console.log("secondMax",secondMax)

Check array is sorted or not

Ganesh K S — Sun, 21 Apr 2024 04:52:20 +0000

This is my given array

const arr=[1,2,6,4,5]

You need traverse through array from the index 1
In each loop check the current element (arr[i]) with previous element
if current element is greater than previous element then continue with loop else break the loop over there

In the first loop

current element is greater than previous element so you can continue with the loop

In the second loop

current element is greater than previous element so you can continue with the loop

In the third loop

current element is lesser than previous element so break the loop

Solution to check array is sorted or not in javascript

let checkSort = true

for(let i=1;i<arr.length;i++){
  if(arr[i] < arr[i-1]]){
    checkSort=false;
    break;
  }
}

if(checkSort){
  console.log("Array is Sorted")
}else{
  console.log("Array is not sorted)
}

Find the largest element within the array

Ganesh K S — Sun, 21 Apr 2024 04:16:13 +0000

this is my given array

const arr=[5,10,4,24,13,8]

*largest is set to first element in the array --- largest = arr[0] *
You need to set the first element to largest
next need to loop from 1 st index to last index
in each loop check if the array value is larger than that in that case largest will be the current iterating element

Program to find the largest element in the array

let largest = arr[0];

for(let i=1;i<arr.length;i++){
  if(arr[i] > largest){
    largest=arr[i]
  }
}

console.log(largest)