L - Black-and-White Cube 简单构造

时间:2021-09-14 19:29:36
L - Black-and-White Cube
Time Limit:1000MS     Memory Limit:262144KB     64bit IO Format:%I64d & %I64u
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Description

You are given a cube of size k × k × k, which consists of unit cubes. Two unit cubes are considered neighbouring, if they have common face.

Your task is to paint each of k3 unit cubes one of two colours (black or white), so that the following conditions must be satisfied:

 

  • each white cube has exactly 2 neighbouring cubes of white color;
  • each black cube has exactly 2 neighbouring cubes of black color.

 

Input

The first line contains integer k(1 ≤ k ≤ 100), which is size of the cube.

Output

Print -1 if there is no solution. Otherwise, print the required painting of the cube consequently by layers. Print a k × k matrix in the firstk lines, showing how the first layer of the cube should be painted. In the following k lines print a k × k matrix — the way the second layer should be painted. And so on to the last k-th layer. Note that orientation of the cube in the space does not matter.

Mark a white unit cube with symbol "w" and a black one with "b". Use the format of output data, given in the test samples. You may print extra empty lines, they will be ignored.

Sample Input

Input
1
Output
-1
Input
2
Output
bb
ww

bb
ww

 

 

int main() { //freopen("in.txt","r",stdin); int k; while(cin>>k) { if(k%2) { cout<<-1<<endl; continue; } repf(i,1,k/2)//i layout { if(i%2 == 0) { repf(j,1,k)//j column { repf(a,1,k/2) { if(j%2) { if(a%2) cout<<"bb"; else cout<<"ww"; }else { if(a%2==0) cout<<"bb"; else cout<<"ww"; } } cout<<endl; } cout<<endl; repf(j,1,k)//j column { repf(a,1,k/2) { if(j%2) { if(a%2) cout<<"bb"; else cout<<"ww"; }else { if(a%2==0) cout<<"bb"; else cout<<"ww"; } } cout<<endl; } cout<<endl; }else { repf(j,1,k) { repf(a,1,k/2) { if(j%2==0) { if(a%2) cout<<"bb"; else cout<<"ww"; }else { if(a%2==0) cout<<"bb"; else cout<<"ww"; } } cout<<endl; } cout<<endl; repf(j,1,k) { repf(a,1,k/2) { if(j%2==0) { if(a%2) cout<<"bb"; else cout<<"ww"; }else { if(a%2==0) cout<<"bb"; else cout<<"ww"; } } cout<<endl; } cout<<endl; } } } return 0; }