深度优先搜索

#include <iostream>
#define MAX 9999
using namespace std;

int main()
{
    int i,j,n,m,cur,head,tail,e[101][101],q[100001],book[101]={0};
    cin>>n>>m;
    for(i=1;i<=n;i++)
        for(j=1;j<=n;j++)
    {
        if(i==j)
            e[i][j]=0;
        else
            e[i][j]=MAX;
    }
    int a,b;
    for(i=1;i<=m;i++)
    {
        cin>>a>>b;
        e[a][b]=1;
        e[b][a]=1;
    }
    head=1;
    tail=1;
    q[tail]=1;
    tail++;
    book[1]++;
    while(head<tail)
    {
        cur=q[head];
        for(i=1;i<=n;i++)
        {
            if(e[cur][i]==1&&book[i]==0)
        {
            q[tail]=i;
            tail++;
            book[i]=1;
        }
        if(tail>n)
            break;
        }
        head++;
    }
    for(int i=1;i<tail;i++)
        cout<<q[i]<<endl;
    return 0;
}