Probleme

///pr1

#include<fstream>
using namespace std;
ifstream cin("dfs.in");
ofstream cout("dfs.out");

void DFS(int k);
int a[105][105];
int v[105];
int n;
int main()
{
    int i,j,k,m,n0,x,y;
    cin>>n>>m>>n0;
    for(i=1;i<=m;i++)
    {
        cin>>x>>y;
        a[x][y]=1;
        a[y][x]=1;
    }
    DFS(n0);

    cin.close();
    cout.close();
    return 0;
}

void DFS(int k)
{
    int i;
    v[k]=1;
    cout<<k<<" ";
    for(i=1;i<=n;i++)
    {
        if(a[k][i]==1 && v[i]==0)
        {
            DFS(i);
        }
    }
}

///
///pr2
//

#include<fstream>

using namespace std;

ifstream cin("soarece.in");
ofstream cout("soarece.out");

void Back(int i,int j,int k);

int di[]={-1,0,1,0};
int dj[]={0,1,0,-1};
int a[105][105];
int n,m,nrp;
int i_start,j_start;
int i_stop,j_stop;
int next_i,next_j;

int main()
{
    int i,j;
    cin>>n>>m;
    for(i=1; i<=n; i++)
    {
        for(j=1; j<=m; j++)
        {
            cin>>a[i][j];
        }
    }

    for(j=0; j<=m+1; j++)
    {
        a[0][j]=a[n+1][j]=1;
    }
    for(i=0; i<=n+1; i++)
    {
        a[i][0]=a[i][m+1]=1;
    }

    cin>>i_start>>j_start;
    cin>>i_stop>>j_stop;

    Back(i_start,j_start,1);

    cout<<nrp;

    cin.close();
    cout.close();

    return 0;
}

void Back(int i,int j,int k)
{
    a[i][j]=k;
    if(i==i_stop && j==j_stop)
    {
        nrp++;
    }
    else
    {
        for(k=0; k<4; k++)
        {
            next_i=i+di[k];
            next_j=j+dj[k];
            if(a[next_i][next_j]==0)
            {
                Back(next_i,next_j,k+1);
            }
        }
    }
    a[i][j]=0;
}


///
///pr3
///

#include<fstream>

using namespace std;

ifstream cin("traseucal.in");
ofstream cout("traseucal.out");

void Back(int i,int j,int k);
int posibil();
void matrice();

int di[]={-2,-2,-1,+1,+2,+2,+1,-1};
int dj[]={-1,+1,+2,+2,+1,-1,-2,-2};
int a[105][105];
int s[105][105];
int n,m,nr;
int i_start,j_start;
int i_stop,j_stop;
int next_i,next_j;

int main()
{
    int i,j;
    cin>>n>>m;
    for(i=1;i<=n;i++)
    {
        for(j=1;j<=m;j++)
        {
            cin>>a[i][j];
        }
    }

    i_start=j_start=1;
    i_stop=n; j_stop=m;

    Back(i_start,j_start,1);

    cin.close();
    cout.close();

    return 0;
}

void Back(int i,int j,int k)
{
    a[i][j]=k;
    s[i][j]=a[i][j];
    if(i==i_stop && j==j_stop && nr==0)
    {
        matrice();
        nr++;
    }
    else
    {
        for(int c=0;c<8;c++)
        {
            next_i=i+di[c];
            next_j=j+dj[c];
            if(posibil()==1)
            {
                Back(next_i,next_j,k+1);
            }
        }
    }
    a[i][j]=0;
}

int posibil()
{
    if((1<=next_i&&next_i<=n)&&(1<=next_j&&next_j<=m)&&a[next_i][next_j]==0)
        return 1;
    else
        return 0;
}

void matrice()
{
    int i,j;
    for(i=1;i<=n;i++)
    {
        for(j=1;j<=m;j++)
        {
            cout<<s[i][j]<<" ";
        }
        cout<<endl;
    }
}


///
///pr4
///

#include<fstream>

using namespace std;

ifstream cin("traseucalmax.in");

void Back(int i,int j,int k);
int posibil();
void matrice();

int di[]={-2,-2,-1,+1,+2,+2,+1,-1};
int dj[]={-1,+1,+2,+2,+1,-1,-2,-2};
int a[105][105];
int s[105][105];
int n,m,nr[105];
int i_start,j_start;
int i_stop,j_stop;
int next_i,next_j;
int maxim=INT_MIN;

int main()
{
    int i,j;
    cin>>n>>m;
    for(i=1;i<=n;i++)
    {
        for(j=1;j<=m;j++)
        {
            cin>>a[i][j];
        }
    }

    i_start=j_start=1;
    i_stop=n; j_stop=m;

    Back(i_start,j_start,1);

    cin.close();

    return 0;
}

void Back(int i,int j,int k)
{
    a[i][j]=k;
    s[i][j]=a[i][j];
    if(i==i_stop && j==j_stop)
    {
        if(k>maxim)
        {
            maxim=k;
            matrice();
        }
    }
    else
    {
        for(int c=0;c<8;c++)
        {
            next_i=i+di[c];
            next_j=j+dj[c];
            if(posibil()==1)
            {
                Back(next_i,next_j,k+1);
            }
        }
    }
    a[i][j]=0;
    s[i][j]=0;
}

int posibil()
{
    if((1<=next_i&&next_i<=n)&&(1<=next_j&&next_j<=m)&&a[next_i][next_j]==0)
        return 1;
    else
        return 0;
}

void matrice()
{
    ofstream cout("traseucalmax.out");

    int i,j;
    for(i=1;i<=n;i++)
    {
        for(j=1;j<=m;j++)
        {
            cout<<s[i][j]<<" ";
        }
        cout<<endl;
    }

    cout.close();
}