01背包问题python 2.7实现

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 #!/usr/bin/env python
 # -*- coding:utf-8 -*-
 class bag():
     def __init__(self,weight,value):
         self.weight = weight
         self.value = value
     def knapsack(self, full_weight):#weight value存数组
         result = [[0 for i in range(full_weight+1)] for i in range(len(self.value)+1)]
         count = len(self.weight)#物品个数
         for n in range(1,count+1):#n当前最大物品个数
             for weight in range(0,full_weight+1):#背包内重量递增
                 if self.weight[n-1]<=weight:#第n个背包的重量为weight[n-1]判断是否小于允许容量
                     if result[n-1][weight]<(result[n-1][weight-self.weight[n-1]]+self.value[n-1]):
                         #如果当前物品在相同重量情况下价值更高
                         result[n][weight]=result[n-1][weight-self.weight[n-1]]+self.value[n-1]
                     else:
                         result[n][weight]=result[n-1][weight]
                 else:
                     result[n][weight] =result[n-1][weight]
         for perrow in result:
             print perrow
         return result
     def find_which(self,full_weight):
         result = self.knapsack(full_weight)
         i= len(result)-1
         j = len(result[i])-1
         while i >=1:
             while j>=1:
                 if result[i-1][j]!=result[i][j]:#说明当前行的东西拿了
                     print '第'+ str(i)+'个'
                     j = j -self.weight[i-1]
                     i = i - 1
                     break
                 else:
                     i = i -1

 def main():
     sort_instance = bag([2,2,6,5,4,1,2,7,5,7,4],[6,3,5,4,6,1,4,7,3,6,1])#重量，价值初始化
     sort_instance.find_which(30)#定义背包总重量

 if __name__ =='__main__':
     main()

实现结果：