01背包和完全背包

来源：互联网发布：淘宝物品拍照技巧编辑：程序博客网时间：2024/06/05 13:27

RT，题目地址http://zju.acmclub.com/index.php?app=problem_title&id=1&problem_id=2123

ps：（1）01背包和完全背包的区别在于计算方向，01背包的计算顺序是从上往下，从右往左；完全背包则是从上往下，从左往右

（2）背包是否装满的区别在于初始化第0行，若不一定装满则全部初始化为0，

若要求必须装满则dp[0]=0,dp[1~C]=（求最小值时初始化为INF，求最大值时初始化为-INF）

（3）最终返回的dp[C]即为结果。

python代码：

#coding=utf-8INF = 1000000def Matrix(rows,cols):    #matrix = [[0 for col in range(cols)] for row in range(rows)]    matrix = [0 for col in range(cols)]    return matrixt = input()while t:    [x,y]=raw_input().split()    C=int(y)-int(x)    lines=input()    n = lines    weight = []    price = []    while lines:        [a,b]=raw_input().split()        weight.append(int(b))        price.append(int(a))        lines -= 1        if lines==0:break    mat = Matrix(n+1,C+1)    #init row-0 in matrix    mat[0]=0    for j in range(1,C+1):mat[j]=INF    #compute the matrix    for i in range(1,n+1):        for j in range(weight[i-1],C+1):            mat[j]=min(mat[j],mat[j-weight[i-1]]+price[i-1])    if mat[C]==INF:print "This is impossible."    else: print "The minimum amount of money in the piggy-bank is %d." % mat[C]    t -= 1    if t==0:break

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