Created
October 20, 2015 19:27
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function santa(data) { | |
// get the names from the first index of the array | |
var names = data.map(a => a.shift()), | |
result = {}; | |
// build the data structure as an object of gifter => giftees | |
names.map((name, i) => result[name] = data[i].map((v, j) => v ? names[j] : false).filter(v => v)); | |
// iterate around each name | |
while (names.length) { | |
// make sure we start with the name that has the fewest choices | |
var name; | |
names = names.sort((a, b) => result[a].length - result[b].length); | |
name = names.shift(); | |
// if we don't have any names left, it must be impossible | |
if (result[name].length == 0) { | |
return false | |
} | |
else { | |
// pick a name at random from the list | |
var selectedName = result[name][Math.floor(result[name].length * Math.random())]; | |
// and set it as the object | |
result[name] = selectedName; | |
// if it's not just a string now... | |
if (typeof result[selectedName] == 'object') { | |
// filter the current name from the list | |
result[selectedName] = result[selectedName].filter(value => value != name); | |
} | |
// filter all the remaining arrays to ensure we can't pick the same one again | |
names.map(currentName => result[currentName] = result[currentName].filter(value => value != selectedName)); | |
} | |
} | |
return result; | |
} | |
/* usage: | |
santa([ | |
["Alice", 0, 0, 1, 1, 1, 1, 1], | |
["Bob", 0, 0, 0, 0, 0, 1, 0], | |
["Carla", 1, 1, 0, 0, 0, 1, 1], | |
["Dan", 1, 1, 0, 0, 0, 1, 1], | |
["Erin", 1, 1, 0, 0, 0, 1, 1], | |
["Frank", 1, 1, 1, 1, 1, 0, 1], | |
["Gary", 1, 1, 1, 1, 1, 1, 0] | |
]); | |
// might return something like: | |
[ | |
["Alice", "Dan"], | |
["Bob", "Erin"], | |
["Carla", "Bob"], | |
["Dan", "Alice"], | |
["Erin", "Frank"], | |
["Frank", "Carla"] | |
] | |
santa([ | |
["Alice", 0, 1, 1, 1, 0, 1], | |
["Bob", 0, 0, 1, 1, 0, 1], | |
["Carla", 0, 1, 0, 1, 0, 1], | |
["Dan", 0, 1, 1, 0, 0, 0], | |
["Erin", 0, 0, 1, 0, 0, 1], | |
["Frank", 1, 1, 1, 1, 1, 0] | |
]); | |
// would always return | |
false | |
santa([ | |
["Alice", 0, 1, 1], | |
["Bob", 1, 0, 1], | |
["Carla", 1, 1, 0] | |
]); | |
// might return something like: | |
[ | |
["Alice", "Bob"], | |
["Bob", "Carla"], | |
["Carla", "Alice"] | |
] | |
*/ |
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