Here is the problem statement:
Take a second to imagine that you are in a room with 100 chairs arranged in a circle. These chairs are numbered sequentially from One to One Hundred. At some point in time, the person in chair #1 will be told to leave the room. The person in chair #2 will be skipped, and the person in chair #3 will be told to leave. Next to go is person in chair #6. In other words, 1 person will be skipped initially, and then 2, 3, 4.. and so on. This pattern of skipping will keep going around the circle until there is only one person remaining- The survivor! Note that each chair is removed when the person leaves the room.
Please review my attempt below considering the following points:
- Correctness (I am getting the winner as # 31)
- Any chances for optimization
var myApp = angular.module('myApp',[]);
myApp.controller('MyCtrl', [ '$scope', '$interval', '$log', function($scope, $interval, $log){
$scope.init = function(){
$scope.people = [];
$scope.logs = [];
// get the 100 people/chair
for(var i=1; i<=100; i++){
$scope.people.push({ index: i });
}
};
$scope.startFiring = function(){
var fireIndex = 0, // for removing the person at this index
skipCount = 0; // for incremental counting
if($scope.people.length >= 1){ // if start button clicked again
$scope.gotWinner = false; // hide the winner
$interval.cancel(fireInterval); // stop the interval
$scope.init();
}
var fireInterval = $interval(function(){
$scope.disableStartButton = true;
if ($scope.people.length > 1) { // if more than 1 people
$scope.logs.push({text: 'Firing #' + $scope.people[fireIndex].index}); // show the log
$scope.people.splice(fireIndex, 1); // fire!
// increment
skipCount += 1;
fireIndex += skipCount;
//if fireIndex becomes greater than $scope.people.length, then set fireIndex to remainder from fireIndex / $scope.people.length
if(fireIndex > $scope.people.length){
fireIndex %= $scope.people.length;
}
} else {
$interval.cancel(fireInterval); // stop the interval
$scope.gotWinner = true; // show the winner
$scope.disableStartButton = false;
}
}, 500); // every 1/2 sec.
};
$scope.init(); // intialize the chair/people when the view is loaded or start is clicked again
}]);body{
font-family: "HelveticaNeue-Light", "Helvetica Neue Light", "Helvetica Neue", Helvetica, Arial, "Lucida Grande", sans-serif;
}
span{
display: inline-block;
padding: 5px;
margin: 4px;
border-radius: 3px;
background: #000000;
color: #FFFFFF;
}<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>JS Bin</title>
</head>
<body ng-app='myApp'>
<div ng-controller="MyCtrl">
<div>
<span ng-repeat="person in people">{{person.index}}</span>
</div>
<button ng-click="startFiring()" ng-disabled="disableStartButton">Start!</button>
<p ng-show="gotWinner">And the winner is.... # <strong>{{people[0].index}}!</strong></p>
<p ng-show="logs.length !== 0">Logs:</p>
<ul>
<li ng-repeat="log in logs | orderBy:'-'">{{log.text}}</li>
</ul>
</div>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.5.0/angular.min.js"></script>
</body>
</html>
100set10. – Ivan Modric Feb 15 at 9:54