CODEWITHSUNDEEP
javascriptarrays
vsync
vsync

Reputation: 130431

Filling arrays equally

given 2 arrays (with max length of lets say 15):

var a = [1,2,3];
var b = [5,6,7,8,9,10,11,12];
var data = [13,14,15,16,17,18,19,20,21,22,23,24,25,26];

what would be the best approach to "fill" arrays a and b equally with the data from data array, so they both be the same length (or as close to it) but not exceed max length?

required result could look like this:

var a = [1,2,3,13,14,15,16,17,18,19,20,21];
var b = [5,6,7,8,9,10,11,12,22,23,24,25,26];

my situation is more complex, and I'm looking for an efficient way: I have 2 sides on the screen, each side might have profile photos of ppl from FB. if there aren't enough photos in one side, I need to add "fake" photos to fill it, so both sides will look more or less evenly filled with photos

Upvotes: 0

Views: 255

Answers (7)

rob
rob

Reputation: 1286

var b = [1,2,3];
var a = [5,6,7,8,9,10,11,12];
var data = [13,14,15,16,17,18,19,20,21,22,23,24,25,26];

// find how many more elements need to be added to the smaller array 
var diff = Math.abs(b.length - a.length);

// get the elements to add to the smallest array
var data1 = data.splice(0, diff + ((data.length - diff) / 2));

// data now only contains the elements that will not be added to the smallest array

if (a.length < b.length) {
    // a is the smallest array
    a.push.apply(a,  data1);
    b.push.apply(b, data);
} else {
    // b is the smallest array
    b.push.apply(b,  data1);
    a.push.apply(a, data);
}

Upvotes: 0

vsync
vsync

Reputation: 130431

my solution was this: 

var a    = [1,2,3];
var b    = [5,6,7,8,9,10,11,12];
var data = [13,14,15,16,17,18,19,20,21,22,23,24,25,26];

var howManyToFill = (data.length + (b.length + a.length)/2)/2;
// take half of the "data" and put it in "a"
a = a.concat(data.slice(0,howManyToFill));
// what's left goes to "b"
b = b.concat(data.slice(howManyToFill));

console.log(a);
console.log(b);

Upvotes: 0

Indranil Mondal
Indranil Mondal

Reputation: 2857

var a    = [1,2,3];
var b    = [5,6,7,8,9,10,11,12];
var data = [13,14,15,16,17,18,19,20,21,22,23,24,25,26];

for( var i = data.length; i--; ){
  if (a.length > b.length)
      b.push(data[i])
  else
      a.push(data[i])
}

console.log(a.length, b.length);

Upvotes: 1

Abraham Hamidi
Abraham Hamidi

Reputation: 13809

Taken from Brad's comment, I imagine you could do something like this:

ab=[];
ab=ab.concat(a,b,data);
del = (a.length + b.length + data.length) / 2;
a = [];
b = [];
for (var i = 0; i < Math.ceil(del); i++) {
    a.push(ab[i]);
    b.push(ab[Math.ceil(del) + i]);
}

Upvotes: 1

Kasravnd
Kasravnd

Reputation: 107347

you want to the last index of a and b have 12 deference and len of final array is 12!!! i think u can use this algorithm ! :

for j in data:
  while ( j-max(a)) == 12 ):
   x++
for i in range(x):
 data[i]=a[i]

and after this delete the indexes with index number mor than 12 !

Upvotes: 0

Bill
Bill

Reputation: 25565

Here is another way without having to loop through the elements:

var a = [1,2,3],
    b = [5,6,7,8,9,10,11,12],
    data = [13,14,15,16,17,18,19,20,21,22,23,24,25,26];

var targetLength = (a.length + b.length + data.length)/2,
    aCnt = Math.ceil(targetLength) - a.length,
    bCnt = Math.floor(targetLength) - b.length;

a = a.concat(data.slice(0, aCnt));
b = b.concat(data.slice(aCnt, data.length));

// a is [1, 2, 3, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22]
// b is [5, 6, 7, 8, 9, 10, 11, 12, 23, 24, 25, 26]

Upvotes: 1

ak0053792
ak0053792

Reputation: 563

Algorithm would be like:

1) Identify the number of elements in a

2) Identify the number of elements in b

3) Identify the number of elements in data

4) if elements in a is less than b, then populate a from data till it becomes equal to b or vice versa

5) if in both a and b elements are equal, and data still having the elements, then populate the array a and b alternatively.

Upvotes: 0

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