全红求助

xingchen666 @ 2023-07-19 17:48:58

#include<bits/stdc++.h>
using namespace std;

const int N = 100;

int n;
int a[N];
int b[N];
int c[N];
int d[N];

int total=0;

void dfs(int i){
    if(i>n){
        total++;
        if(total<=3){
            for(int k=1;k<=n;k++){
                cout<<a[k]<<' ';
            }
            cout<<endl;
        }
        return;
    }
    for(int j=1;j<=n;j++){
        if(b[j]==0 && c[i+j]==0 && d[i-j+2*n]==0){
            a[i] = j;
            b[j] = 1;
            c[i+j] = 1;
            d[i-j+2*n] = 1;

            dfs(i+1);

            b[i] = 0;
            c[i+j] = 0;
            d[i-j+n] = 0;

        }
    }
}

int main(){
    cin>>n;

    dfs(1);
    cout<<total;

    return 0;
}

by wanglexi @ 2023-08-05 11:38:58

34行b[i]应该和上面一样是b[j]，36行d[i-j+n]也应该和上面一样是d[i-j+2*n]。

AC代码：

#include<bits/stdc++.h>
using namespace std;

const int N = 100;

int n;
int a[N];
int b[N];
int c[N];
int d[N];

int total=0;

void dfs(int i){
    if(i>n){
        total++;
        if(total<=3){
            for(int k=1;k<=n;k++){
                cout<<a[k]<<' ';
            }
            cout<<endl;
        }
        return;
    }
    for(int j=1;j<=n;j++){
        if(b[j]==0 && c[i+j]==0 && d[i-j+2*n]==0){
            a[i] = j;
            b[j] = 1;
            c[i+j] = 1;
            d[i-j+2*n] = 1;

            dfs(i+1);

            b[j] = 0;
            c[i+j] = 0;
            d[i-j+2*n] = 0;

        }
    }
}

int main(){
    cin>>n;

    dfs(1);
    cout<<total;

    return 0;
}

by wanglexi @ 2023-08-05 11:56:01

以后，可以复制上面的

b[j] = 1;
c[i+j] = 1;
d[i-j+2*n] = 1;

改所赋的值

b[j] = 0;
c[i+j] = 0;
d[i-j+2*n] = 0;

这样可以一定程度上减少出类似的错