function solve(arr) {
    var name,
        type,
        taskNumber,
        score,
        lines;
    var result = {};
    for (var i = 0; i < arr.length; i++) {
        var obj = arr[i];
        var split = obj.split('&');
        name = split[0].trim();
        type = split[1].trim();
        taskNumber = split[2].trim();
        score = Number(split[3].trim());
        lines = Number(split[4].trim());
        taskNumber = 'Task ' + taskNumber;
        if (!(taskNumber in result)) {
            result[taskNumber] = {'tasks': [], 'average': 0, 'lines': 0};
        }
        result[taskNumber]['tasks'].push({'name': name, 'type': type});
        result[taskNumber]['average'] += score;
        result[taskNumber]['lines'] += lines;
    }
    for (var obj1 in result) {
        var avg = result[obj1].average / result[obj1].tasks.length;
        result[obj1].average = Math.round(avg * 100) / 100;
        result[obj1].tasks.sort(function (x, y) {
            return x.name.localeCompare(y.name);
        });
    }

    var a = [];
    var i = 0;
    for (var obj2 in result) {
        a.push({});
        a[i][obj2] = result[obj2];
        i++;
    }
    a.sort(function (x, y) {
        var xKey = Object.keys(x)[0];
        var yKey = Object.keys(y)[0];
        if (x[xKey].average !== y[yKey].average) {
            return y[yKey].average - x[xKey].average;
        }
        return x[xKey].lines - y[yKey].lines;
    })
    var json = JSON.stringify(a);
    json = json.substring(1, json.length-1).replace(/}},{/g, '},');
    console.log(json);
}

var arr = ['Array Matcher & strings & 4 & 100 & 38',
    'Magic Wand & draw & 3 & 100 & 15',
    'Dream Item & loops & 2 & 88 & 80',
    'Knight Path & bits & 5 & 100 & 65',
    'Basket Battle & conditionals & 2 & 100 & 120',
    'Torrent Pirate & calculations & 1 & 100 & 20',
    'Encrypted Matrix & nested loops & 4 & 90 & 52',
    'Game of bits & bits & 5 & 100 & 18',
    'Fit box in box & conditionals & 1 & 100 & 95',
    'Disk & draw & 3 & 90 & 15',
    'Poker Straight & nested loops & 4 & 40 & 57',
    'Friend Bits & bits & 5 & 100 & 81'];
solve(arr);