Diagonally Print a Square Array

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Description

Given an sqaure array (n*n) of integers, print elements diagonally .

Example

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let nums = [
	[1,2,3],
	[4,5,6],
	[7,8,9]
]

should print the following:
1
2 4
3 5 7
6 8
9

Solution: O(n^2)

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function printDiagnally(input){
	let n = input.length       // 3
	let lines = 2*(n-1) + 1   	// 5

	// determine how many diagonal lines
	for( let sum = 0; sum < lines; sum++ ){

		// determine the starting x-coord, and starting y-coord
		let x0 = sum < n ? sum : n-1
		let y0 = sum - x0
		let num = Math.abs(x0 - y0) +1   // how many elements in this line
		let str = ""

		// concat all elements in this line
		for( let x = x0; x > x0-num; x-- ){
			let y = sum - x
			str = input[x][y] + " "+str
		}
		console.log(str)
	}
}

// ---------- Testing: ------------
console.log("Test1: ")
let input = [[1]]
printDiagnally(input)


console.log("Test2: ")
input = [
	[1,  2],
	[3,  4]
]
printDiagnally(input)


console.log("Test3: ")
input = [
	[1, 2, 3],
	[4, 5, 6],
	[7, 8, 9],
]
printDiagnally(input)

console.log("Test4: ")
input = [
	[1,  2,  3,  4 ],
	[5,  6,  7,  8 ],
	[9,  10, 11, 12],
	[13, 14, 15, 16],
]
printDiagnally(input)