Question

here is my problem: I have 5 arrays of integer like these in javascript:

array1 = [0, 1, 2, 3, 4];
array2 = [9, 1, 2, 3, 4];
array3 = [10, 1, 2, 11, 4];
array4 = [12, 1, 2, 13, 4];
array5 = [14, 1, 2, 15, 4];

I have to find the longest common subarray. In this case I have to retrieve the following subarray: [1, 2, 4].

For the records, I won’t find repetitions inside arrays and my main goal is not execution speed.

thanks

Answer 1

Try this:

var array1 = [0, 1, 2, 3, 4];
var array2 = [9, 1, 2, 3, 4];
var array3 = [10, 1, 2, 11, 4];
var array4 = [12, 1, 2, 13, 4];
var array5 = [14, 1, 2, 15, 4];

// join everything into one array
var all = array1.join(',')+','+array2.join(',')+','+array3.join(',')+','+array4.join(',')+','+array5.join(',');
all = all.split(',');

// get an object with all unique numbers as keys
var keys = {};
for(var i=0; i<all.length; i++) keys[all[i]] = 1;
console.log(keys);

// generate an array with values present in all arrays
var common = [];
for(var x in keys) {
  if(array1.indexOf(parseInt(x)) != -1 && array2.indexOf(parseInt(x)) != -1 && array3.indexOf(parseInt(x)) != -1 && array4.indexOf(parseInt(x)) != -1 && array5.indexOf(parseInt(x)) != -1) {
    common.push(x);
  }
}
console.log(common);