Question 1 -- Write a function that accepts an integer N and generates an NxN spiral matrix
Example
input: N=2
output:
[
[1, 2],
[4, 3]
]
input: N=3
output:
[
[1, 2, 3],
[8, 9, 4],
[7, 6, 5]
]
Given a 2D array (matrix) inputMatrix of integers, create a function spiralCopy that copies inputMatrix’s values into a 1D array in a spiral order, clockwise. Your function then should return that array.
Example
input: inputMatrix = [ [1, 2, 3, 4, 5],
[6, 7, 8, 9, 10],
[11, 12, 13, 14, 15],
[16, 17, 18, 19, 20] ]
output: [1, 2, 3, 4, 5, 10, 15, 20, 19, 18, 17, 16, 11, 6, 7, 8, 9, 14, 13, 12]
/**
* Spiral Matrix Generation
* @author MadhavBahl
* @date 24/01/2019
*/
function spiralGeneration (num) {
let spiral = [],
topRow = 0,
btmRow = num-1,
leftCol = 0,
rightCol = num-1,
count = 1;
// Initialize the spiral matrix with zeros
for (let i=0; i<num; i++) {
let thisRow = [];
for (let j=0; j<num; j++)
thisRow.push (0);
spiral.push (thisRow);
}
// Populate the matrix
while ((topRow<=btmRow) && (leftCol<=rightCol)) {
// Populate the top row
for (let i=leftCol; i<=rightCol; i++)
spiral[topRow][i] = count++;
topRow++;
// Populate the right column
for (let i=topRow; i<=btmRow; i++)
spiral[i][rightCol] = count++;
rightCol--;
// Populate the bottom row IF toprow has not become greater than bottom row
if (topRow <= btmRow) {
for (let i=rightCol; i>=leftCol; i--)
spiral[btmRow][i] = count++;
btmRow--;
}
// Populate the left column IF rightCol has not become less than left Col
if (rightCol >= leftCol) {
for (let i=btmRow; i>=topRow; i--)
spiral[i][leftCol] = count++;
leftCol++;
}
}
// Print the result
console.log (spiral);
return spiral;
}
spiralGeneration (2);
spiralGeneration (3);
spiralGeneration (4);
spiralGeneration (5);function spiralCopy(inputMatrix) {
// your code goes here
let outputArray = [],
numRow = inputMatrix.length,
numCol = inputMatrix[0].length;
let topRow = 0,
btmRow = numRow - 1,
leftCol = 0,
rightCol = numCol - 1;
while ((topRow <= btmRow) && (leftCol <= rightCol)) {
for (let i=leftCol; i<=rightCol; i++) {
outputArray.push(inputMatrix[topRow][i]);
}
topRow++;
for (let i=topRow; i<=btmRow; i++) {
outputArray.push(inputMatrix[i][rightCol]);
}
rightCol--;
if (topRow <= btmRow) {
for (let i=rightCol; i>=leftCol; i--) {
outputArray.push(inputMatrix[btmRow][i]);
}
btmRow--;
}
if (leftCol <= rightCol) {
for (let i=btmRow; i>=topRow; i--) {
outputArray.push(inputMatrix[i][leftCol]);
}
leftCol++;
}
}
return outputArray;
}
console.log(spiralCopy([ [1, 2, 3, 4],
[6, 7, 8, 9],
[11, 12, 13, 14],
[16, 17, 18, 19] ]));
// Should print [ 1, 2, 3, 4, 9, 14, 19, 18, 17, 16, 11, 6, 7, 8, 13, 12 ]
console.log(spiralCopy([ [1, 2, 3, 4, 5],
[6, 7, 8, 9, 10],
[11, 12, 13, 14, 15],
[16, 17, 18, 19, 20] ]));
// Should print [ 1, 2, 3, 4, 5, 10, 15, 20, 19, 18, 17, 16, 11, 6, 7, 8, 9, 14, 13, 12 ]