POJ 1276 Cash Machine

很容易看出来是一个背包问题，开始把每一张钞票都跑了一遍01背包，直接TLE了。

其实就是多重背包模板题。

//#include <bits/stdc++.h>
#include <iostream>
#include <utility>
#include <vector>
#include <cstring>
using namespace std;
#define fst first
#define scd second
#define pb(x) push_back((x))
#define mkp(x,y) make_pair((x),(y)) 
#define ist(x) insert((x))
typedef long long ll;
typedef pair<int ,int > pii;
typedef pair<ll ,ll > pll;
typedef vector< int > vi;
ll gcd(ll a,ll b){ return b==0?a:gcd(b,a%b);}
ll qPow(ll a,ll b,ll mod){ ll ret=1ll;while(b){ if(b&1) ret=ret*a%mod;a=a*a%mod;b>>=1;} return ret; }

pii nD[13];
int dp[100000+5];
int nValue;

void ZeroOnePack(int cost , int weight){
    for(int i=nValue;i>=cost;i--)
        dp[i]=max(dp[i],dp[i-cost]+weight);
}

void CompletePack(int cost , int weight){
    for(int i=cost;i<=nValue;++i)
        dp[i]=max(dp[i],dp[i-cost]+weight);
}

void MultiplePack(int cost ,int weight,int amount){
    if(cost*amount>=nValue) CompletePack(cost , weight);
    else{
        int k=1;
        while(k<amount){
            ZeroOnePack(k*cost,k*weight);
            amount-=k;
            k<<=1;
        }
        ZeroOnePack(amount*cost,amount*weight);
    }
}

int main(){
    int cash,N;
    while(cin>>cash>>N){
        nValue=cash;
        memset(dp,0,sizeof(dp));
        for(int i=0;i<N;++i)
            cin>>nD[i].first>>nD[i].second;
        for(int i=0;i<N;++i){
            MultiplePack(nD[i].second,nD[i].second,nD[i].first);
        }    
        cout<<dp[cash]<<endl;
    }
    return 0;
}