【USACO 1.4】Mother's Milk

/*
TASK: milk3
LANG: C++
SOLVE: 倒水，dfs，枚举每一种倒法，ca[i][j]记录a和c桶的状态，因为总体积不变，故b的状态不需要记录。
 */
#include<cstdio>
#include<iostream>
#include<cstring>
#include<algorithm>
using namespace std;
int a,b,c;
bool ca[30][30];
void dfs(int na,int nb,int nc){
//    printf("%d %d %d\n",na,nb,nc);
    if(ca[na][nc])return;
    ca[na][nc]=1;
    dfs(max(na+nb-b,0),min(b,na+nb),nc);//a->b
    dfs(min(a,na+nb),max(na+nb-a,0),nc);//b->a
    dfs(max(na+nc-c,0),nb,min(c,na+nc));//a->c
    dfs(min(a,na+nc),nb,max(na+nc-a,0));//c->a
    dfs(na,max(nc+nb-c,0),min(c,nc+nb));//b->c
    dfs(na,min(nc+nb,b),max(nc+nb-b,0));//c->b
}
int main(){
    freopen("milk3.in","r",stdin);
    freopen("milk3.out","w",stdout);
    scanf("%d%d%d",&a,&b,&c);
    dfs(0,0,c);
    int ok=0;
    for(int i=0;i<=c;i++)
        if(ca[0][i]){
            if(ok) printf(" ");
            printf("%d",i);
            ok=1;
        }
    puts("");
    return 0;
}