Created
July 5, 2013 08:19
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<!doctype html> | |
<html ng-app> | |
<head> | |
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.0.7/angular.min.js"></script> | |
</head> | |
<body> | |
<div ng-controller="nQueensController"> | |
<label>Number:</label> | |
<input type="number" ng-model="n" placeholder="Enter a number"> | |
<ul> | |
<li ng-repeat="s in solutions"> | |
Solutions for: {{ s.n }} queens: {{ s.count }} | |
</li> | |
</ul> | |
</div> | |
</body> | |
</html> | |
<script type="text/javascript"> | |
function nQueensController($scope) { | |
$scope.n = 2; | |
$scope.solutions = []; | |
var solve = function() { | |
$scope.solutions = []; | |
var n = $scope.n; | |
for (i = 0; i < n; i++) { | |
var obj = {n: i, count: 0}, | |
mask = (1 << i) - 1; | |
var solveF = function(columns, leftDiag, rightDiag) { | |
var poss = ~(columns|leftDiag|rightDiag) & mask; | |
while (poss > 0) { | |
var bit = -poss & poss; // valid position | |
c = columns | bit; | |
poss = poss ^ bit; | |
ol = (leftDiag | bit) << 1; | |
or = (rightDiag | bit) >> 1; | |
solveF(c,ol,or); | |
} | |
if (columns === mask){ | |
obj.count += 1; | |
} | |
} | |
solveF(0,0,0); | |
$scope.solutions.push(obj); | |
} | |
} | |
$scope.$watch('n', solve); | |
} | |
</script> |
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