diner.js

var util = require('util');

var diners = [[[], [], [], []],
              [[], [], [], []],
              [[], [], [], []],
              [[], [], [], []]];

var seen = []; 
for(var i = 0; i < 20; i ++) 
  seen[i] = []; 

for(var i = 0; i < 4; i ++) {
  for(var j = 0; j < 4; j ++) {
    for(var k = 0; k < 5; k ++) {
      for(var l = 0; l < 20; l ++) {
        var found = false;
        for(var m = 0; m < diners[i][j].length; m++) {
          if(seen[l].indexOf(diners[i][j][m]) !== -1) {
            found = true;
            break;
          }   
        }   
        for(var m = 0; m < 4; m ++) {
          if(diners[i][m].indexOf(l) !== -1) {
            found = true;
            break;
          }   
        }   
        if(found)
          continue;
        for(var m = 0; m < diners[i][j].length; m ++) {
          seen[diners[i][j][m]].push(l);
          seen[l].push(diners[i][j][m]);
        }   
        diners[i][j].push(l);
        break;
      }   
    }   
  }
}

console.log(util.inspect(diners));