cap, cup

cap_cup.js

function unique(arr) {
  var ret = [];
  for(var i=0, l=arr.length; i<l; i++) {
    for(var j=i+1; j<l; j++) {
      if (arr[i] === arr[j]) j = ++i;
    }
    ret.push(arr[i]);
  }
  return ret;
};

function cup(arr) {
  return unique(Array.prototype.concat.apply([], arr));
}


function cap(arr) {
  if (!arr.length) return [];
  var current = ret = arr.shift(), target;
  var n = 0, len = arr.length;
  while(n < len) {
    ret = [], target = arr[n++];
    for(var i=0, l=current.length; i<l; i++) {
      for(var j=0, l2=target.length; j<l2; j++) {
        if (current[i] === target[j]) ret.push(current[i]);
      }
    }
    current = ret;
  }
  return unique(ret);
};

var sample1 = [
  [1,6,9,4,5,2,2,4],
  [3,6,3,6,6,2,3],
  [1,8,9,4,2,8,3,2],
  [1,2,2,9,5,5,4,6],
  [0,1,9,6,5,4,2,6],
  [2,7,9,8,1,1,3,7],
  [4,3,7,0,1,8,2,7]
];

console.log(sample1.slice());
console.log(cap(sample1.slice()));
console.log(cup(sample1.slice()));

var N = 10000;
console.time("cap");
for (var i=0; i<N; i++) var v1 = cap(sample1.slice())
console.timeEnd("cap");

console.time("cup");
for (var i=0; i<N; i++) var v1 = cup(sample1.slice())
console.timeEnd("cup");