USACO Party Lamps

 1 /*{
 2 ID:a4298442
 3 PROB:lamps
 4 LANG:C++
 5 }
 6 */
 7 #include<iostream>
 8 #include<fstream>
 9 #include<cstring>
10 #include<algorithm>
11 #define maxn 109
12 using namespace std;
13 ifstream fin("lamps.in");
14 ofstream fout("lamps.out");
15 //#define fin cin
16 //#define fout cout
17 int lamp[maxn],temp[maxn],n1,n2,a[maxn],b[maxn];
18 struct T
19 {
20     char ch[maxn]; 
21 }ans[maxn];
22 void but1(int n)
23 {
24     for(int i=1;i<=n;i++)lamp[i]^=1;
25 }
26 void but2(int n)
27 {
28     for(int i=1;i<=n;i+=2)lamp[i]^=1;
29 }
30 void but3(int n)
31 {
32     for(int i=2;i<=n;i+=2)lamp[i]^=1;
33 }
34 void but4(int n)
35 {
36     for(int i=0;i*3+1<=n;i++)lamp[i*3+1]^=1;
37 }
38 int check(int n,int c,int count_now)
39 {
40     for(int i=1;i<n1;i++)if(lamp[a[i]]==0)return 0;
41     for(int i=1;i<n2;i++)if(lamp[b[i]]==1)return 0;
42     if(count_now>c)return 0;
43     int u=c-count_now;
44     if(u&1)return 0;
45     return 1;
46 }
47 int cmp(T x, T y)
48 {
49     return strcmp(x.ch+1,y.ch+1)>=0?false:true;
50 }
51 int main()
52 {
53     int n,c;
54     fin>>n>>c;
55         while(fin>>a[++n1]&&a[n1]!=-1);
56     while(fin>>b[++n2]&&b[n2]!=-1);
57     for(int i=1;i<=n;i++)temp[i]=1;
58     int h=0;
59     for(int i=0;i<=(1LL<<4)-1;i++)
60     {
61         int count_now=0;
62         memcpy(lamp,temp,sizeof(lamp));
63         for(int j=1,idx=1;j<=i;j<<=1,idx++)if((i&j)!=0 )
64         {
65             count_now++;
66             if(idx==1)but1(n);
67             if(idx==2)but2(n);
68             if(idx==3)but3(n);
69             if(idx==4)but4(n);
70         }
71         if(check(n,c,count_now))
72         {
73             h++;
74             for(int i=1;i<=n;i++)
75             {
76                 ans[h].ch[i]=lamp[i]+‘0‘;
77             }
78         }
79     }
80     if(h==0)fout<<"IMPOSSIBLE"<<endl;else
81     {
82         sort(ans+1,ans+1+h,cmp);
83         for(int i=1;i<=h;i++)fout<<ans[i].ch+1<<endl;
84     }
85     return 0;
86 }