DFS+状态位
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1 #include<iostream> 2 using namespace std; 3 4 int chess=0; 5 int step; 6 bool flag=false; 7 int ri[16],cj[16]; 8 9 bool isopen(void) 10 { 11 if(chess==0xFFFF) 12 return true; 13 else 14 return false; 15 } 16 17 void flip(int bit) 18 { 19 chess=chess^(1<<bit); 20 int row=bit/4; 21 int col=bit%4; 22 for(int c=0;c<4;c++) 23 chess=chess^(1<<(row*4+c)); 24 for(int r=0;r<4;r++) 25 chess=chess^(1<<(r*4+col)); 26 return; 27 } 28 29 void dfs(int bit,int deep) 30 { 31 if(deep==step) 32 { 33 flag=isopen(); 34 return; 35 } 36 37 if(flag||bit>15)return; 38 39 ri[deep]=bit/4; 40 cj[deep]=bit%4; 41 42 flip(bit); 43 dfs(bit+1,deep+1); 44 45 flip(bit); 46 dfs(bit+1,deep); 47 return; 48 } 49 50 int main(void) 51 { 52 char ch; 53 for(int i=0;i<4;i++) 54 for(int j=0;j<4;j++) 55 { 56 cin>>ch; 57 if(ch=='-') chess=chess^(1<<(i*4+j)); 58 } 59 60 for(step=0;step<=16;step++) 61 { 62 dfs(0,0); 63 if(flag) break; 64 } 65 66 cout<<step<<endl; 67 for(int i=0;i<step;i++) 68 cout<<ri[i]+1<<' '<<cj[i]+1<<endl; 69 return 0; 70 }
