设有n种物品，每一种物品数量无限。第i种物品每件重量为wi公斤，每件价值ci元。现有一只可装载重量为W公斤的背包，求各种物品应各取多少件放入背包，使背包中物品的价值最高。-with n product, every kind of infinite number of copies. I first product for each weight wi kilograms, each worth ci yuan. Existing a carrying weight of the backpack W kilograms, should seek various items each for the number of pieces Add backpack, so backpack maximum value items.