knapsack.js

function optimize () {
    var budget = 50000;
    var current_salary = 0;
    var team = [];
    var constraints = {
        'QB': 1,
        'RB': 2,
        'WR': 3,
        'TE': 1,
        'DST': 1,
        'FLEX': 1
    };
    var counts = {
        'QB': 0,
        'RB': 0,
        'WR': 0,
        'TE': 0,
        'DST': 0,
        'FLEX': 0
    };

    for (var i in $rootScope.players) {
        var pos = $rootScope.players[i].position;
        var sal = $rootScope.players[i].salary;

        if (counts[pos] < constraints[pos] && current_salary + sal <= budget) {
            team.push($rootScope.players[i]);
            counts[pos]++;
            current_salary += sal;
        }
        else if (counts['FLEX'] < constraints['FLEX'] && current_salary + sal <= budget && ['RB','WR','TE'].indexOf(pos) !== -1) {
            team.push($rootScope.players[i]);
            counts['FLEX']++;
            current_salary += sal;
        }
    }

    $rootScope.players.sort( function (a, b) {
        return b.dk_total - a.dk_total;
    });

    for (var j in $rootScope.players) {
        var pos = $rootScope.players[j].position;
        var sal = $rootScope.players[j].salary;
        var pts = $rootScope.players[j].dk_total;

        if (team.indexOf($rootScope.players[j]) === -1) {
            var pos_players = team.filter( function (player) {
                return player.position === pos;
            })
            pos_players.sort( function (a, b) {
                return a.dk_total - b.dk_total;
            });

            for (var k in pos_players) {
                if (((current_salary + sal - pos_players[k].salary) <= budget) && (pts > pos_players[k].dk_total)) {
                    team[team.indexOf(pos_players[k])] = $rootScope.players[j];
                    current_salary = current_salary + sal - pos_players[k].salary;
                    break;
                }
            }
        }
    }
    return team;
};