BZOJ 1531 POI2005 Bank notes

Posted 2020-10-06

多重背包问题，二进制拆分后做~

#include <cstdio>
#include <algorithm>
#include <cstring>
 
#define up(a,b,c) for(register int c=a;c<=b;++c)
#define down(a,b,c) for(register int c=a;c>=b;--c)
 
typedef long long ll;
ll n,x;
ll num[205],value[205],Aim,v[200005],Count=1,dp[2000005],Size[200005];
 
int main(){
//  freopen("in.in","r",stdin);
//    freopen("myout.out","w",stdout);
    scanf("%lld",&n);
    up(1,n,i) scanf("%lld",&value[i]);
    up(1,n,i){
        scanf("%lld",&x);
        for(int j=1;j<=x;j<<=1){
            v[Count] = j*value[i];
            Size[Count++]=j;
            x-=j;
        }
        if(x>0){
            v[Count]=x*value[i];
            Size[Count++]=x;
        }
    }
    scanf("%lld",&Aim);
    memset(dp,0x3f3f3f3f,sizeof(dp));
    dp[0]=0;
    //printf("%d\n",Count);
    /*for(int i=1;i<Count;i++){
        printf("v[%d]:%d Size[%d]:%d\n",i,v[i],i,Size[i]);
    }*/
    for(int i=1;i<Count;i++){
        for(int j=Aim;j>=v[i];j--){
            dp[j] = std::min(dp[j],dp[j-v[i]]+Size[i]);
            //printf("dp[%d]:%d\n",j,dp[j]);
        }
    }
    printf("%lld\n",dp[Aim]);
    return 0;
}