高级算法——贪心算法（背包问题）

贪心算法不能用来解决离散物品问题的原因是我们无法将“ 半台电视” 放入背包。 规则是按照物品价值高低顺序放入背包。

    function ksack(values, weights, capacity) {
        var load = 0;
        var i = 0;
        var v = 0;
        while (load < capacity && i < weights.length) {
            if (weights[i] <= (capacity - load)) {
                v += values[i];
                load += weights[i];
            } else {
                var r = (capacity - load) / weights[i];
                v += r * values[i];
                load += weights[i];
            }
            ++i;
        }
        return v;
    }
    var items = [ "A", "B", "C", "D" ];
    var values = [ 50, 140, 60, 60 ];
    var weights = [ 5, 20, 10, 12 ];
    var capacity = 30;
    document.write(ksack(values, weights, capacity)); // 显示 220