hdu 1195 双向bfs

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http://acm.hdu.edu.cn/showproblem.php?pid=1195
这代码好长，不过好多重复的内容。
#include <iostream>#include <queue>#include <cstring>using namespace std;struct node{    int x, step;};int vis[10000];node q1[10000];node q2[10000];int c[5],d[5];int ss[2]={1,-1};void hash1(int x){    for(int i = 3; i>=0; i--)    {        c[i] = x%10;        x/=10;    }}int rehash(){    int a = 0;    for(int i = 0; i<4; i++)        a = a*10+d[i];    return a;}int front1,front2,tail1,tail2,tmp;int bfs(int a, int b){    front1=front2=tail1=tail2=0;    node temp;    temp.x=a;    temp.step=0;    q1[tail1++] = temp;    temp.x=b;    temp.step=0;    q2[tail2++]=temp;    vis[a]=1;    vis[b]=2;    while(front1<tail1||front2<tail2)    {        tmp = tail1;        for(; front1<tmp; front1++)        {            temp = q1[front1];            hash1(temp.x);            for(int k = 0; k<2; k++)            {                for(int i = 0; i<4; i++)                {                    for(int j = 0; j<4; j++)                        d[j]=c[j];                    d[i]+=ss[k];                    if(k==0&&d[i]>9)                        d[i] = 1;                    else if(k==1&&d[i]<1)                        d[i] = 9;                    int ans = rehash();                    if(vis[ans]!=1)                    {                         if(vis[ans]==2)                        {                            int cnt;                            for(cnt=1; cnt<tail2; cnt++)                            if(q2[cnt].x==ans)                                break;                            return q2[cnt].step+q1[front1].step+1;                        }                        vis[ans] = 1;                        temp.x = ans;                        temp.step = q1[front1].step+1;                        q1[tail1++] = temp;                    }                }            }            for(int i = 0; i<3; i++)            {                for(int j = 0; j<4; j++)                    d[j] = c[j];                int o = d[i];                d[i] = d[i+1];                d[i+1] = o;                int ans = rehash();                if(vis[ans]!=1)                {                    if(vis[ans]==2)                    {                        int cnt;                        for(cnt=1; cnt<tail2; cnt++)                            if(q2[cnt].x==ans)                                break;                        return q2[cnt].step+q1[front1].step+1;                    }                    vis[ans] = 1;                    temp.x = ans;                    temp.step = q1[front1].step+1;                    q1[tail1++] = temp;                }            }        }        tmp = tail2;        for(; front2<tmp; front2++)        {            temp = q2[front2];            hash1(temp.x);            for(int k = 0; k<2; k++)            {                for(int i = 0; i<4; i++)                {                    for(int j = 0; j<4; j++)                        d[j]=c[j];                    d[i]+=ss[k];                    if(k==0&&d[i]>9)                        d[i] = 1;                    else if(k==1&&d[i]<1)                        d[i] = 9;                    int ans = rehash();                    if(vis[ans]!=2)                    {                        if(vis[ans]==1)                        {                            int cnt;                            for(cnt = 1; cnt<tail1; cnt++)                            if(q1[cnt].x==ans)                                    break;                            return q1[cnt].step+q2[front2].step+1;                        }                        vis[ans] = 2;                        temp.x = ans;                        temp.step = q2[front2].step+1;                        q2[tail2++] = temp;                    }                }            }            for(int i = 0; i<3; i++)            {                for(int j = 0; j<4; j++)                    d[j] = c[j];                int o = d[i];                d[i] = d[i+1];                d[i+1] = o;                int ans = rehash();                if(vis[ans]!=2)                {                    if(vis[ans]==1)                    {                        int cnt;                        for(cnt = 1; cnt<tail1; cnt++)                            if(q1[cnt].x==ans)                                break;                        return q1[cnt].step+q2[front2].step+1;                    }                    vis[ans] = 2;                    temp.x = ans;                    temp.step = q2[front2].step+1;                    q2[tail2++] = temp;                }            }        }    }    return 0;}int main(){    int t,a,b;    cin>>t;    while(t--)    {        memset(vis,0,sizeof(vis));        cin>>a>>b;        int ans = bfs(a,b);        cout<<ans<<endl;    }}
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