C++实现八皇后问题

C++实现八皇后问题

#include <iostream>
using std::cout;
using std::endl;

#include <iomanip>
using std::setw;

#include <cmath>
//非递归算法解决八皇后问题。求出可能的92种。
// using std::abs;

int main()
{
	static int queen[9];
	static int count=1;

	for (int A=1;A<=8;A++)
	{
		for (int B=1;B<=8;B++)
		{
			if (B==A)
			{
				continue;
			}

			queen[2]=B;
			if ((abs(B-A))==1)
			{
				continue;
			}
			queen[1]=A;
			
			for (int C=1;C<=8;C++)
			{
				if ((C==B) || (C==A))
				{
					continue;
				}

				if ((abs(C-B)==1)||(abs(C-A)==2))
				{
					continue;
				}
				queen[3]=C;

				for (int D=1;D<=8;D++)
				{
					if ((D==C)||(D==B)||(D==A))
					{
						continue;
					}

					if ((abs(D-C)==1)||(abs(D-B)==2)||(abs(D-A)==3))
					{
						continue;
					}
					queen[4]=D;

					for (int E=1;E<=8;E++)
					{
						if ((E==D)||(E==C)||(E==B)||(E==A))
						{
							continue;
						}

						if ((abs(E-D)==1)||(abs(E-C)==2)||(abs(E-B)==3)||(abs(E-A)==4))
						{
							continue;
						}
						queen[5]=E;

						for (int F=1;F<=8;F++)
						{
							if ((F==E)||(F==D)||(F==C)||(F==B)||(F==A))
							{
								continue;
							}

							if ((abs(F-E)==1)||(abs(F-D)==2)||(abs(F-C)==3)||(abs(F-B)==4)||(abs(F-A)==5))
							{
								continue;
							}
							queen[6]=F;

							for (int G=1;G<=8;G++)
							{
								if ((G==F)||(G==E)||(G==D)||(G==C)||(G==B)||(G==A))
								{
									continue;
								}

								if ((abs(G-F)==1)||(abs(G-E)==2)||(abs(G-D)==3)||(abs(G-C)==4)||(abs(G-B)==5)||(abs(G-A)==6))
								{
									continue;
								}
								queen[7]=G;

								for (int I=1;I<=8;I++)
								{
									if ((I==G)||(I==F)||(I==E)||(I==D)||(I==C)||(I==B)||(I==A))
									{
										continue;
									}

									if ((abs(I-G)==1)||(abs(I-F)==2)||(abs(I-E)==3)||(abs(I-D)==4)||(abs(I-C)==5)
										||(abs(I-B)==6)||(abs(I-A)==7))
									{
										continue;
									}
									queen[8]=I;

									cout<<"  NO."<<setw(2)<<count<<": ";
									for (int i=1;i<=8;i++)
									{
										cout<<setw(3)<<queen[i]; 
									}
									count++;
									cout<<endl;
								}
							}
						}
					}
				}
			}
		}
	}

	return 0;
}
　　

 

#include <iostream>
using namespace std;
//递归算法解决八皇后问题。总共有92种解法。
int c[20], n=8, cnt=0;
void print(){

    for(int i=0; i<n; ++i){
        for(int j=0; j<n; ++j){
            if(j == c[i]) cout<<"1 ";
            else cout<<"0 ";
        }
        cout<<endl;
    }
    cout<<endl;
}
void search(int r){
    if(r == n){
        print();
        ++cnt;
        return;
    }
    for(int i=0; i<n; ++i){
        c[r] = i;
        int ok = 1;
        for(int j=0; j<r; ++j)
            if(c[r]==c[j] || r-j==c[r]-c[j] || r-j==c[j]-c[r]){
                ok = 0;
                break;
            }
        if(ok) search(r+1);
    }
}
int main(){
    search(0);
    cout<<cnt<<endl;
    return 0;
}