function getResult() {
function add(a, b) { return a + b; }
function check(count, constraint) {
return function (b, i) {
return !b || b <= count * constraint[i];
};
}
function iter(data, count, level) {
var temp;
count[level] = count[level] || 0;
count = count.slice();
if (level + 1 === constraints.items.length) {
while (!data.every(check(count[level], constraints.items[level].data))) {
count[level]++;
}
temp = {
count: count,
cost: count.map(function (a, i) {
return a * constraints.items[i].cost;
})
};
temp.total = temp.cost.reduce(add, 0);
result.push(temp);
return;
}
do {
iter(data, count, level + 1);
if (!data.reduce(add, 0)) {
break;
}
data = data.map(function (a, j) {
return Math.max(0, a - constraints.items[level].data[j]);
});
count[level]++;
} while (true);
}
var result = [];
iter(constraints.requirements.data.slice(), [], 0);
return result;
}
var constraints = {
requirements: { data: [8, 2, 15, 4], optimum: 'min' },
items: [
{ data: [10, 2, 3, 4], cost: 200 },
{ data: [3, 1, 2, 3], cost: 120 },
{ data: [1, 1, 1, 1], cost: 75 }
]
},
result = getResult(),
optimum = result.reduce(function (r, a, i) {
if (!i || a.total === Math[constraints.requirements.optimum](r[0].total, a.total)) {
return [a];
}
r[0].total === a.total && r.push(a);
return r;
}, []);
document.write("<pre>optimum: " + JSON.stringify(optimum, 0, 4) + "</pre>");
document.write("<pre>result: " + JSON.stringify(result, 0, 4) + "</pre>");