"Learn the process of determining the complete perimeter of various shapes through a JavaScript exercise and create a functional method

Question

"Learn the process of determining the complete perimeter of various shapes through a JavaScript exercise and create a functional method

During an internship interview, I encountered a complex logical exercise that I couldn't solve. If you could provide some assistance and explain the solution to me, I would greatly appreciate it (even though I didn't pass the interview). The exercise is as follows:

"Given an array arr of strings, complete the function landPerimeter by calculating the total perimeter of all the islands. Land areas are marked with 'X' while water fields are represented as 'O'. Each tile is considered a 1 x 1 piece of land. Here are some examples for better visualization: ['XOOXO', 'XOOXO', 'OOOXO', 'XXOXO', 'OXOOO']

View image here :

Expected result: "Total land perimeter: 24", while
['XOOO', 'XOXO', 'XOXO', 'OOXX', 'OOOO']

View image here:

Expected result: "Total land perimeter: 18"

I kindly request a code example demonstrating how to solve this exercise. Thank you in advance!

javascript function

Answer 1

Answer №1

Below is a link that you may find helpful: find-perimeter-shapes-formed-1s-binary-matrix. If needed, some minor adjustments can be made based on your specific case.

<script>

function numOfNeighbour( mat,  i,  j,rows,cols) 
{ 
    var count = 0;   

    // UP 
    if (i > 0  && mat[i - 1][j]==='X') 
        count++; 

    // LEFT 
    if (j > 0  && mat[i][j - 1]==='X')         
        count++; 

    // DOWN 
    if (i < rows-1  && mat[i + 1][j]==='X')         
        count++; 

    // RIGHT 
    if (j < cols-1 && mat[i][j + 1]==='X')         
        count++; 

    return count; 
} 

function findPerimeter( mat) 
{ 
    var perimeter = 0; 
    var rows=mat.length;
    var cols=mat[0].length;

    // Traversing the matrix and finding ones to 
    // calculate their contribution. 
    for (var i = 0; i < rows; i++) 
        for (var j = 0; j < cols; j++) 
            if (mat[i][j] && mat[i][j]==='X') 
                perimeter += (4 - numOfNeighbour(mat, i ,j,rows,cols)); 

    return perimeter; 
} 

console.log("perimeter of ['XOOXO', 'XOOXO', 'OOOXO', 'XXOXO', 'OXOOO'] is ",findPerimeter(['XOOXO', 'XOOXO', 'OOOXO', 'XXOXO', 'OXOOO'])); //24
console.log("perimeter of ['XOOO', 'XOXO', 'XOXO', 'OOXX', 'OOOO'] is "     ,findPerimeter(['XOOO', 'XOXO', 'XOXO', 'OOXX', 'OOOO'])); //18
</script>

Answer 2

Below is a link that you may find helpful: find-perimeter-shapes-formed-1s-binary-matrix. If needed, some minor adjustments can be made based on your specific case.

<script>

function numOfNeighbour( mat,  i,  j,rows,cols) 
{ 
    var count = 0;   

    // UP 
    if (i > 0  && mat[i - 1][j]==='X') 
        count++; 

    // LEFT 
    if (j > 0  && mat[i][j - 1]==='X')         
        count++; 

    // DOWN 
    if (i < rows-1  && mat[i + 1][j]==='X')         
        count++; 

    // RIGHT 
    if (j < cols-1 && mat[i][j + 1]==='X')         
        count++; 

    return count; 
} 

function findPerimeter( mat) 
{ 
    var perimeter = 0; 
    var rows=mat.length;
    var cols=mat[0].length;

    // Traversing the matrix and finding ones to 
    // calculate their contribution. 
    for (var i = 0; i < rows; i++) 
        for (var j = 0; j < cols; j++) 
            if (mat[i][j] && mat[i][j]==='X') 
                perimeter += (4 - numOfNeighbour(mat, i ,j,rows,cols)); 

    return perimeter; 
} 

console.log("perimeter of ['XOOXO', 'XOOXO', 'OOOXO', 'XXOXO', 'OXOOO'] is ",findPerimeter(['XOOXO', 'XOOXO', 'OOOXO', 'XXOXO', 'OXOOO'])); //24
console.log("perimeter of ['XOOO', 'XOXO', 'XOXO', 'OOXX', 'OOOO'] is "     ,findPerimeter(['XOOO', 'XOXO', 'XOXO', 'OOXX', 'OOOO'])); //18
</script>

"Learn the process of determining the complete perimeter of various shapes through a JavaScript exercise and create a functional method

Answer №1

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