01背包模板题 hdu2602 Bonecollector

由于数组的滚动过程中当前值(i,j)的更新需要用到上一层的(i-1,j-wi)的值，所以在更新当前的j之前不能更新上一层的j之前的值，故01背包是从后向前更新的（重量取值是从大到小的）。

代码如下：

#include<bits/stdc++.h>
using namespace std;
typedef unsigned int ui;
typedef long long ll;
typedef unsigned long long ull;
#define pf printf
#define mem(a,b) memset(a,b,sizeof(a))
#define prime1 1e9+7
#define prime2 1e9+9
#define pi 3.14159265
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1
#define scand(x) scanf("%llf",&x) 
#define f(i,a,b) for(int i=a;i<=b;i++)
#define fm(i,a,b) for(int i=a;i>=b;i--)
#define scan(a) scanf("%d",&a)
#define dbg(args) cout<<#args<<":"<<args<<endl;
#define pb(i) push_back(i)
#define ppb(x) pop_back(x)
#define inf 0x3f3f3f3f
#define maxn 100005
int n,m,t,vol;
int w[maxn],v[maxn],dp[maxn];
int main()
{
    //freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);
    std::ios::sync_with_stdio(false);
    scan(t);
    while(t--)
    {
        scan(n);scan(vol);
        f(i,1,n)
        scan(v[i]);
        f(i,1,n)scan(w[i]);
        mem(dp,0);
        for(int i=1;i<=n;i++)
            for(int j=vol;j>=w[i];j--)
            {
                    dp[j]=max(dp[j],dp[j-w[i]]+v[i]);
            }
            pf("%d
",dp[vol]);
     } 
 }