BZOJ 1716 [Usaco2006 Dec]The Fewest Coins 找零钱

Posted 2020-10-07

题目思维难度不大，二进制优化多重背包+完全背包组合。

但是我居然傻逼了WA了7次。

 

#include <cstdio>
#include <algorithm>
#include <cstring>
using std::min;
const int INF=0x3f3f3f3f;

int dp[113333];
int shop[113333];
int n,t,Count,Min=INF;
int coin[105],has;
int V[23333],Size[23333];


int main(){
    memset(dp,INF,sizeof(dp));
    memset(shop,INF,sizeof(shop));
    dp[0]=0;
    shop[0]=0;
    scanf("%d%d",&n,&t);
    for(int i=1;i<=n;i++){
        scanf("%d",&coin[i]);
        for(int j=coin[i];j<=t*3;++j){
            shop[j] = min(shop[j],shop[j-coin[i]]+1);
        }
    }
    for(int i=1;i<=n;++i){
        scanf("%d",&has);
        for(int j=1;j<=has;j<<=1){
            V[Count] = j*coin[i];
            Size[Count++] = j;
            has-=j;
        }
        if(has>0){
            V[Count] = has*coin[i];
            Size[Count++] = has;
        }
    }
    for(int i=0;i<=Count;++i){
        for(int j=3*t;j>=V[i];--j){
            dp[j] = min(dp[j],dp[j-V[i]]+Size[i]);
        }
    }
    //for(int i=0;i<=3*t;i++) printf("dp[%d]:%d\\n",i,dp[i]);
    for(int j=t;j<=3*t;++j){
        if(dp[j]!=INF && shop[j-t]!=INF){
            Min = min(Min,dp[j]+shop[j-t]);
        }
    }
    if(Min==INF) printf("-1");
    else printf("%d\\n",Min);
    return 0;
}