01背包问题python 2.7实现
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1 #!/usr/bin/env python 2 # -*- coding:utf-8 -*- 3 class bag(): 4 def __init__(self,weight,value): 5 self.weight = weight 6 self.value = value 7 def knapsack(self, full_weight):#weight value存数组 8 result = [[0 for i in range(full_weight+1)] for i in range(len(self.value)+1)] 9 count = len(self.weight)#物品个数 10 for n in range(1,count+1):#n当前最大物品个数 11 for weight in range(0,full_weight+1):#背包内重量递增 12 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 13 if result[n-1][weight]<(result[n-1][weight-self.weight[n-1]]+self.value[n-1]): 14 #如果当前物品在相同重量情况下价值更高 15 result[n][weight]=result[n-1][weight-self.weight[n-1]]+self.value[n-1] 16 else: 17 result[n][weight]=result[n-1][weight] 18 else: 19 result[n][weight] =result[n-1][weight] 20 for perrow in result: 21 print perrow 22 return result 23 def find_which(self,full_weight): 24 result = self.knapsack(full_weight) 25 i= len(result)-1 26 j = len(result[i])-1 27 while i >=1: 28 while j>=1: 29 if result[i-1][j]!=result[i][j]:#说明当前行的东西拿了 30 print '第'+ str(i)+'个' 31 j = j -self.weight[i-1] 32 i = i - 1 33 break 34 else: 35 i = i -1 36 37 38 def main(): 39 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 40 sort_instance.find_which(30)#定义背包总重量 41 42 if __name__ =='__main__': 43 main()
实现结果：
