Pairs

by rishul matta

JavaScript

function pairs(numbers, difference) {
	if (numbers === undefined) {
  	return 0;
  }
    var mapOfPairs = {};
    var count = 0;

    for (i = 0; i < numbers.length; ++i) {
        var firstNos = numbers[i];

        for (j = i + 1; j < numbers.length; ++j) {
            var secondNos = numbers[j];

            var key = firstNos.toString() + secondNos.toString();
            var reverseKey = secondNos.toString() + firstNos.toString();

            if (mapOfPairs[key] === undefined) {
                mapOfPairs[key] = true;
                mapOfPairs[reverseKey] = true;

                if (Math.abs(firstNos - secondNos) === difference) {
                    count++;
                }
            }
        }
    }

    return count;
}


// pairs([1,1,4,5,7,8,9], 3)