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,,n)
         scan(v[i]);
         f(i,,n)scan(w[i]);
         mem(dp,);
         for(int i=;i<=n;i++)
             for(int j=vol;j>=w[i];j--)
             {
                     dp[j]=max(dp[j],dp[j-w[i]]+v[i]);
             }
             pf("%d\n",dp[vol]);
      }
  }