基础01背包问题

http://www.51nod.com/onlineJudge/questionCode.html#!problemId=1085

http://hihocoder.com/problemset/problem/1038?sid=320857

在N件物品取出若干件放在容量为W的背包里，每件物品的体积为W1，W2……Wn（Wi为整数），与之相对应的价值为P1,P2……Pn（Pi为整数）。求背包能够容纳的最大价值。

动态转移方程    dp[i][j]=max(dp[i-1][j],dp[i-1][j-v[i]]+w[i]);  

背包九讲里面讲的很好。

#include <iostream>
#include <cstdio>
#include <cmath>
#include <vector>
#include <cstring>
#include <string>
#include <algorithm>
#include <string>
#include <set>
#include <functional>
#include <numeric>
#include <sstream>
#include <stack>
#include <map>
#include <queue>

#define CL(arr, val)    memset(arr, val, sizeof(arr))

#define ll long long
#define inf 0x7f7f7f7f
#define lc l,m,rt<<1
#define rc m + 1,r,rt<<1|1
#define pi acos(-1.0)

#define L(x)    (x) << 1
#define R(x)    (x) << 1 | 1
#define MID(l, r)   (l + r) >> 1
#define Min(x, y)   (x) < (y) ? (x) : (y)
#define Max(x, y)   (x) < (y) ? (y) : (x)
#define E(x)        (1 << (x))
#define iabs(x)     (x) < 0 ? -(x) : (x)
#define OUT(x)  printf("%I64d
", x)
#define lowbit(x)   (x)&(-x)
#define Read()  freopen("a.txt", "r", stdin)
#define Write() freopen("b.txt", "w", stdout);
#define maxn 1000000000
#define N 100010
using namespace std;

int n,m;
int f[N];
void ZeroOnePack(int cost,int weight)
{
    for(int v=m;v>=cost;v--)
        f[v]=max(f[v],f[v-cost]+weight);
}
int main()
{
   //Read();
   //Write();
   int a,b;
    while(~scanf("%d%d",&n,&m))
    {
        memset(f,0,sizeof(f));
        for(int i=0;i<n;i++)
        {
            scanf("%d%d",&a,&b);
            ZeroOnePack(a,b);
        }
        printf("%d
",f[m]);
    }
    return 0;
}