unique-pairs.js

// ## Coding
// Given an array of positive integers, write a function which returns all the unique pairs which add (equal) up to 100.

// Example data:
var sample_input = [0, 1, 100, 99, 0, 10, 90, 30, 55, 33, 55, 75, 50, 51, 49, 50, 51, 49, 51];
// sample_output = [[1,99], [0,100], [10,90], [51,49], [50,50]]


function findUniquePairs(array){
  var pairs = [];

  for(var i = 0; i < array.length; i++){
    var num1 = array[i];

    for(var j=0; j < array.length; j++){

      var num2 = array[j];

      if(num1 + num2 === 100 && !exists(num1, num2, pairs)){
        pairs.push([num1, num2]);
      }
    }
  }

  return pairs;

}

function exists(num1, num2, array){
  var exists = false;

  for(var i = 0; i < array.length; i++){
    var pair = array[i];
    if(pair.indexOf(num1) > -1 && pair.indexOf(num2) > -1){
      return true;
    }
  }
}



console.log(findUniquePairs(sample_input))