knightmoves.js

"use strict";

function Graph(){
	this.vertices = {};

	//graph.addVertex('vFrom', {'vTo1': 1, 'vTo2': 1});
	this.addVertex = function(name, edges) {
		this.vertices[name] = edges;
	}

}

/** 
* [0,0] coordinates represents A1 square
*/
function Chessboard() {
	var cols = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'];
	var rows = [1, 2, 3, 4, 5, 6, 7, 8];

	// x[+,-][1], y[+,-][2]
	// x[+,-][2], y[+,-][1]
	this.knightMoves = function (x, y) {
		var result = [];
		
		function addIfValid(x1, y1) {
			if (x1 < 0 || x1 > cols.length -1 || y1 < 0 || y1 > rows.length -1) return;
			result.push(cols[x1] + rows[y1]);
		}
		
		addIfValid(x+1, y+2);
		addIfValid(x+1, y-2);

		addIfValid(x-1, y+2);
		addIfValid(x-1, y-2);

		addIfValid(x+2, y+1);
		addIfValid(x+2, y-1);
			
		addIfValid(x-2, y+1);
		addIfValid(x-2, y-1);
		
		return result;
	}
	
	this.squareName = function (x, y) {
		return cols[x] + rows[y];
	}
	
	this.forEach = function(func){
		for(var x=0; x < cols.length; x++) {
			for(var y=0; y<rows.length; y++) {
				func(x, y);
			}	
		}
	}
}


(function findSolution(){

	var chessboard = new Chessboard();

	var x=0, y=0;
	var moves = chessboard.knightMoves(x, y);
	console.log('Possible moves from %s: %s', chessboard.squareName(x, y),  moves);

	var x=2, y=2;
	var moves = chessboard.knightMoves(x, y);
	console.log('Possible moves from %s: %s', chessboard.squareName(x, y),  moves);


	var graph = new Graph();
	//graph.addVertex('a1', {'b3': 1, 'c2': 1});

	chessboard.forEach(function(x,y){
		var moves = chessboard.knightMoves(x, y);
		console.log(chessboard.squareName(x, y), moves);
		//graph.addVertex(cols[x] + rows[y], moves);

	});
})();