bzoj 2073: [POI2004]PRZ

2333，暴力，枚举集合再枚举子集。。（一开始判时间直接sb到每一次都重算，，呵呵呵，真是虚傻弱，，）

#include <bits/stdc++.h>
#define LL long long
#define inf 0x3f3f3f3f
using namespace std;
inline int ra()
{
    int x=0,f=1; char ch=getchar();
    while (ch<'0' || ch>'9') {if (ch=='-') f=-1; ch=getchar();}
    while (ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();}
    return x*f;
}
int W,n;
int f[1<<17],w[20],t[20],sum[1<<17];
int main(int argc, char const *argv[])
{
    W=ra(); n=ra();
    for (int i=1; i<=n; i++)
        t[i]=ra(),w[i]=ra();
    for (int i=0; i<=(1<<n); i++) f[i]=inf;
    for (int i=0; i<n; i++)
        f[(1<<i)]=t[i+1],sum[(1<<i)]=w[i+1];
    for (int i=1; i<(1<<n); i++)
    {
        for (int j=i&(i-1); j; j=i&(j-1))
        {
            if (sum[j]+sum[i-j]<=W) f[i]=min(f[i],max(f[j],f[i-j]));
            else f[i]=min(f[i],f[i-j]+f[j]);
            sum[i]=sum[j]+sum[i-j];
        }
    }
    cout<<f[(1<<n)-1];
    return 0;
}