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：