3.5 KiB
3.5 KiB
title | id | challengeType |
---|---|---|
Josephus problem | 5a23c84252665b21eecc7ec5 | 5 |
Description
Instructions
Tests
tests:
- text: <code>josephus</code> should be a function.
testString: assert(typeof josephus=='function','<code>josephus</code> should be a function.');
- text: <code>josephus(30,3)</code> should return a number.
testString: assert(typeof josephus(30,3)=='number','<code>josephus(30,3)</code> should return a number.');
- text: <code>josephus(30,3)</code> should return <code>29</code>.
testString: assert.equal(josephus(30,3),29,'<code>josephus(30,3)</code> should return <code>29</code>.');
- text: <code>josephus(30,5)</code> should return <code>3</code>.
testString: assert.equal(josephus(30,5),3,'<code>josephus(30,5)</code> should return <code>3</code>.');
- text: <code>josephus(20,2)</code> should return <code>9</code>.
testString: assert.equal(josephus(20,2),9,'<code>josephus(20,2)</code> should return <code>9</code>.');
- text: <code>josephus(17,6)</code> should return <code>2</code>.
testString: assert.equal(josephus(17,6),2,'<code>josephus(17,6)</code> should return <code>2</code>.');
- text: <code>josephus(29,4)</code> should return <code>2</code>.
testString: assert.equal(josephus(29,4),2,'<code>josephus(29,4)</code> should return <code>2</code>.');
Challenge Seed
function josephus (init, kill) {
// Good luck!
}
Solution
function josephus (init, kill) {
var Josephus = {
init: function(n) {
this.head = {};
var current = this.head;
for (var i = 0; i < n - 1; i++) {
current.label = i + 1;
current.next = {
prev: current
};
current = current.next;
}
current.label = n;
current.next = this.head;
this.head.prev = current;
return this;
},
kill: function(spacing) {
var current = this.head;
while (current.next !== current) {
for (var i = 0; i < spacing - 1; i++) {
current = current.next;
}
current.prev.next = current.next;
current.next.prev = current.prev;
current = current.next;
}
return current.label;
}
}
return Josephus.init(init).kill(kill)
}