Is there a more efficient method to replace the element at arr[i] without using arr.splice() that is not timing

Question

Is there a more efficient method to replace the element at arr[i] without using arr.splice() that is not timing

Having trouble with my solution and suspect that the .splice() function might be in the wrong place since I keep timing out.

The issue:

You have an array of integers. Each move allows you to increase one element by one. Find the minimum number of moves needed to get a strictly increasing sequence from the input.

Example

If inputArray = [1, 1, 1], then arrayChange(inputArray) should equal 3.

My Pseudo code

First, check if the current index is greater than the next index. If not, continue checking through the loop. If yes, add one to the next index and repeat until true. Increment the "moves" variable each time you increase the next index by one. Return the total moves in the end.

function arrayChange(inputArray) { 
   
    for( var i = 0; i < inputArray.length; i++){
        var addition = (inputArray[i+1]+1)
        if(inputArray[i] >= inputArray[i+1]){     
           inputArray.splice(i,0, addition);
        }
    }

    return inputArray;
}

My Error:

Test 1: Execution time limit exceeded. The program took too long to complete execution. Ensure it finishes quickly for all possible inputs.

javascript arrays loops

Answer 1

Answer №1

Reason for Code Failure:

for( var i = 0; i < inputArray.length; i++){//iterate until reaching end of array
    var addition =(inputArray[i+1]+1);
    if(inputArray[i] >= inputArray[i+1]){  //if its not increasing   
       inputArray.splice(i,0, addition);
    }
}

Let's analyze a given input:

arrayChange([1,1]);

In this case, inputArray[i] equals 1, and inputArray[i+1] equals 1. This causes the code to enter the if statement, as 1>=1. Therefore, it adds 1+1 into the array, but not at the end - rather at position 0. Resulting in:

[2,1,1]

The loop continues:

[2,2,2....,1,1]

This cycle is infinite.

To fix this issue, you need to stop at array.length-1 :

for( var i = 0; i < inputArray.length-1; i++){

You must also insert at the correct index and remove one:

inputArray.splice(i+1,1,addition);

Alternative Approach Without Modifying Array:

function numchanges(array){
  var before=array[0],counter=0;
  for(var i=1;i<array.length;i++){
    if(before>=array[i]){
      //we need to change array[i] to before+1, so:
      counter+=(++before)-array[i];
    }else{
     before=array[i];
   }
  }
return counter;
}

console.log(numchanges([1,1,1]));//should return 3

How It Works: A strictly monotonically increasing function would have values like this:

[1,2,3,4,5,10]

One array and its valid counterpart:

[1,1,3,4,5,-1]
[1,2,3,4,5,6]

Calculating the changes needed:

[0,1,0,0,0,7] => 8

The above code keeps track of the valid number (before) and the necessary change while moving from left to right. We start with the first array element:

before=array[0];//1

We then check if we need to make a change starting from i=1. If the current number is valid:

before<array[i]

We proceed:

before=array[i];
i++;//due to the for loop

If the number is invalid, we calculate the correction required:

result+=before+1-array[i];

For example, if before was 5 and now we have -10, we need to adjust it to 6:

result+=6--10//==16

This means we need another 16 corrections...

Answer 2

Reason for Code Failure:

for( var i = 0; i < inputArray.length; i++){//iterate until reaching end of array
    var addition =(inputArray[i+1]+1);
    if(inputArray[i] >= inputArray[i+1]){  //if its not increasing   
       inputArray.splice(i,0, addition);
    }
}

Let's analyze a given input:

arrayChange([1,1]);

In this case, inputArray[i] equals 1, and inputArray[i+1] equals 1. This causes the code to enter the if statement, as 1>=1. Therefore, it adds 1+1 into the array, but not at the end - rather at position 0. Resulting in:

[2,1,1]

The loop continues:

[2,2,2....,1,1]

This cycle is infinite.

To fix this issue, you need to stop at array.length-1 :

for( var i = 0; i < inputArray.length-1; i++){

You must also insert at the correct index and remove one:

inputArray.splice(i+1,1,addition);

Alternative Approach Without Modifying Array:

function numchanges(array){
  var before=array[0],counter=0;
  for(var i=1;i<array.length;i++){
    if(before>=array[i]){
      //we need to change array[i] to before+1, so:
      counter+=(++before)-array[i];
    }else{
     before=array[i];
   }
  }
return counter;
}

console.log(numchanges([1,1,1]));//should return 3

How It Works: A strictly monotonically increasing function would have values like this:

[1,2,3,4,5,10]

One array and its valid counterpart:

[1,1,3,4,5,-1]
[1,2,3,4,5,6]

Calculating the changes needed:

[0,1,0,0,0,7] => 8

The above code keeps track of the valid number (before) and the necessary change while moving from left to right. We start with the first array element:

before=array[0];//1

We then check if we need to make a change starting from i=1. If the current number is valid:

before<array[i]

We proceed:

before=array[i];
i++;//due to the for loop

If the number is invalid, we calculate the correction required:

result+=before+1-array[i];

For example, if before was 5 and now we have -10, we need to adjust it to 6:

result+=6--10//==16

This means we need another 16 corrections...

Is there a more efficient method to replace the element at arr[i] without using arr.splice() that is not timing

Answer №1

Similar questions

Coordinate the timing of CSS animation with the loading of the page

Modifying the row background in a DataTables drawCallback

Enabling postcss compatibility with jss in Material UI

Troubleshooting: ng-disabled feature is not properly functioning with Bootstrap buttons

Preventing Context Menu from Appearing on Long Click in HTML5 Games

Using Express to request data from Mongo database and only receiving the path

Trigger an Angular2 component function from an HTML element by simply clicking a button

What is the best way to remove quotes from a normal array that has been inserted into an HTML dataset?

Typescript declaration specifies the return type of function properties

Differences in performance between Angular and JQuery_execution times

Is it more effective to import an entire library or specific component when incorporating it into Create-React-App?

Having trouble getting the Html onload function to work in Google Sheets App Script?

How can we map a promise that resolves to foo to a new promise that resolves to bar?

Everything seems to be functioning properly on the local server, but once the media files or players (mp3 and mp4) are uploaded, the background fails to work entirely

Error loading Azure Active Directory web form: Server returned a 401 status code for the requested resource

Sometimes the AngularJS scope is refreshed only intermittently

Determine the area and perimeter of a triangle using the lengths of the sides provided

Order dates within an array by year in descending order, followed by arranging by month in ascending order, and then sorting

React component making an Axios request only receives the initial state as a response

The middleware for express body-parser stores information in the "name" property