BFS_最短路径

已知若干个城市的地图，求从一个城市到另一个城市的路径，要求路径中经过的城市最少。

#include<iostream>
#include<cstring>
using namespace std;
int ju[9][9]=
{{0,0,0,0,0,0,0,0,0},
{0,1,0,0,0,1,0,1,1},
{0,0,1,1,1,0,1,1,1},
{0,0,1,0,0,1,1,1,1},
{0,0,1,0,1,1,1,0,1},
{0,1,1,0,1,1,1,0,0},
{0,0,0,1,1,1,1,1,0},
{0,1,1,1,0,0,1,1,0},
{0,1,1,1,1,0,0,0,1}};
int a[101],b[101],s[9],head,tail;
void print(int d)
{
    cout << char(a[d]+64);
    while(b[d]){
        d=b[d];
        cout << "--" << char(a[d]+64);
    }
    cout << endl;
}
void bfs()
{
    int i;
    head=0;tail=1;         //tail依次记录每个节点 
    a[1]=1;b[1]=0;s[1]=1;  //a数组记录每个节点上城市,b数组记录上一个城市的节点,s记录走过的城市 
    do{
        head++;
        for(i=1;i<=8;i++){
            if(ju[a[head]][i]==0 && s[i]==0){
                tail++;
                a[tail]=i;
                b[tail]=head;
                s[i]=1;
                if(i==8) {
                    print(tail);
                    return;
                }
            }
        }
    }while(head<tail);
}
int main()
{
    memset(s,0,sizeof(s));
    bfs();
    return 0;
}