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fix unbound knapsack problem with items more than 1(default value) (#73)

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Sina Sharafzadeh
2018-06-18 17:20:02 +04:30
committed by Oleksii Trekhleb
parent 6d413d897d
commit 8c206a9976
2 changed files with 54 additions and 1 deletions
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5
src/algorithms/sets/knapsack-problem/Knapsack.js
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@ -165,7 +165,10 @@ export default class Knapsack {
const availableWeight = this.weightLimit - this.totalWeight;
const maxPossibleItemsCount = Math.floor(availableWeight / currentItem.weight);
if (maxPossibleItemsCount) {
if (maxPossibleItemsCount > currentItem.itemsInStock) {
currentItem.quantity = currentItem.itemsInStock;
this.selectedItems.push(currentItem);
} else if (maxPossibleItemsCount) {
currentItem.quantity = maxPossibleItemsCount;
this.selectedItems.push(currentItem);
}

50
src/algorithms/sets/knapsack-problem/__test__/Knapsack.test.js
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@ -96,6 +96,31 @@ describe('Knapsack', () => {
new KnapsackItem({ value: 20, weight: 2 }), // v/w ratio is 10
];
const maxKnapsackWeight = 15;
const knapsack = new Knapsack(possibleKnapsackItems, maxKnapsackWeight);
knapsack.solveUnboundedKnapsackProblem();
expect(knapsack.totalValue).toBe(84 + 20 + 12 + 10 + 5);
expect(knapsack.totalWeight).toBe(15);
expect(knapsack.selectedItems.length).toBe(5);
expect(knapsack.selectedItems[0].toString()).toBe('v84 w7 x 1');
expect(knapsack.selectedItems[1].toString()).toBe('v20 w2 x 1');
expect(knapsack.selectedItems[2].toString()).toBe('v10 w1 x 1');
expect(knapsack.selectedItems[3].toString()).toBe('v12 w3 x 1');
expect(knapsack.selectedItems[4].toString()).toBe('v5 w2 x 1');
});
it('should solve unbound knapsack problem with items in stock', () => {
const possibleKnapsackItems = [
new KnapsackItem({ value: 84, weight: 7, itemsInStock: 3 }), // v/w ratio is 12
new KnapsackItem({ value: 5, weight: 2, itemsInStock: 2 }), // v/w ratio is 2.5
new KnapsackItem({ value: 12, weight: 3, itemsInStock: 1 }), // v/w ratio is 4
new KnapsackItem({ value: 10, weight: 1, itemsInStock: 6 }), // v/w ratio is 10
new KnapsackItem({ value: 20, weight: 2, itemsInStock: 8 }), // v/w ratio is 10
];
const maxKnapsackWeight = 17;
const knapsack = new Knapsack(possibleKnapsackItems, maxKnapsackWeight);
@ -109,4 +134,29 @@ describe('Knapsack', () => {
expect(knapsack.selectedItems[1].toString()).toBe('v20 w2 x 1');
expect(knapsack.selectedItems[2].toString()).toBe('v10 w1 x 1');
});
it('should solve unbound knapsack problem with items in stock and max weight more than sum of all items', () => {
const possibleKnapsackItems = [
new KnapsackItem({ value: 84, weight: 7, itemsInStock: 3 }), // v/w ratio is 12
new KnapsackItem({ value: 5, weight: 2, itemsInStock: 2 }), // v/w ratio is 2.5
new KnapsackItem({ value: 12, weight: 3, itemsInStock: 1 }), // v/w ratio is 4
new KnapsackItem({ value: 10, weight: 1, itemsInStock: 6 }), // v/w ratio is 10
new KnapsackItem({ value: 20, weight: 2, itemsInStock: 8 }), // v/w ratio is 10
];
const maxKnapsackWeight = 60;
const knapsack = new Knapsack(possibleKnapsackItems, maxKnapsackWeight);
knapsack.solveUnboundedKnapsackProblem();
expect(knapsack.totalValue).toBe((3 * 84) + (2 * 5) + (1 * 12) + (6 * 10) + (8 * 20));
expect(knapsack.totalWeight).toBe((3 * 7) + (2 * 2) + (1 * 3) + (6 * 1) + (8 * 2));
expect(knapsack.selectedItems.length).toBe(5);
expect(knapsack.selectedItems[0].toString()).toBe('v84 w7 x 3');
expect(knapsack.selectedItems[1].toString()).toBe('v20 w2 x 8');
expect(knapsack.selectedItems[2].toString()).toBe('v10 w1 x 6');
expect(knapsack.selectedItems[3].toString()).toBe('v12 w3 x 1');
expect(knapsack.selectedItems[4].toString()).toBe('v5 w2 x 2');
});
});