UVALive 5738 Robot Navigation

//UVALive 5738 Robot Navigation/*bfs加上路数标记QUES1:忘记在终点位置，路程一样的方位的路径数是可以相加起来的QUES2:终点位置的路径数累加起来后忘记求余数QUES3:给初始位置的路径数赋予初值时忘记求余数AUTHOR:liweijie08/4/2013*/#include <iostream>#include <cstdio>#include <cstring>#include <queue>#define MAXN 1010#define MAX_INT (int)0x7FFFFFFFusing namespace std;struct node{    long long times;    int dis;}s[MAXN][MAXN][4];char plantmap[MAXN][MAXN];struct coor{    int x;    int y;    int dir;//    int dis;};int M,N,m;coor st,ed;const int walk[][2] = {{-1,0},                 {0,+1},                 {+1,0},                 {0,-1}                };void init(){    for (int i=0;i<M;i++)    {        for (int j=0;j<N;j++)        {            for (int z=0;z<4;z++)            {                s[i][j][z].dis = MAX_INT;                s[i][j][z].times = 0;            }        }    }}bool check(coor to_check){    if (to_check.x==st.x&&to_check.y==st.y)        return true;    if (to_check.x==ed.x&&to_check.y==ed.y)        return true;    if (to_check.x>=0&&to_check.x<M&&to_check.y>=0&&to_check.y<N&&plantmap[to_check.x][to_check.y]!='*')        return true;    return false;}void bfs(){    queue<coor> qu;    while(!qu.empty()) qu.pop();    coor now,next;    qu.push(st);    while(!qu.empty())    {        now = qu.front();        qu.pop();        if (now.x==ed.x&&now.y==ed.y) break;        next.x = now.x;        next.y = now.y;        int dis = s[now.x][now.y][now.dir].dis+1;        for (int i=1;i<4;i+=2)        {            next.dir = (now.dir+i)%4;            if (check(next)==true)            {                if (dis<s[next.x][next.y][next.dir].dis)                {                    s[next.x][next.y][next.dir].dis = dis;                    s[next.x][next.y][next.dir].times = s[now.x][now.y][now.dir].times;                    qu.push(next);                }                else                {                    if (dis==s[next.x][next.y][next.dir].dis)                    {                        s[next.x][next.y][next.dir].times = (s[next.x][next.y][next.dir].times+s[now.x][now.y][now.dir].times)%m;                    }                }            }        }        next.x = now.x+walk[now.dir][0];        next.y = now.y+walk[now.dir][1];        next.dir = now.dir;        if (check(next)==true)        {            if (dis<s[next.x][next.y][next.dir].dis)            {                s[next.x][next.y][next.dir].dis = dis;                s[next.x][next.y][next.dir].times = s[now.x][now.y][now.dir].times;                qu.push(next);            }            else            {                if (dis==s[next.x][next.y][next.dir].dis)                {                    s[next.x][next.y][next.dir].times = (s[next.x][next.y][next.dir].times+s[now.x][now.y][now.dir].times)%m;                }            }        }    }}int main(){    int ct = 0;    while(scanf("%d %d %d",&M,&N,&m)==3)    {        if (m==0) break;        ct++;        printf("Case %d: %d ",ct,m);        for (int i=0;i<M;i++)        {            getchar();            for (int j=0;j<N;j++)            {                scanf("%c",&plantmap[i][j]);            }        }        char d;        scanf("%d %d %d %d %c",&st.x,&st.y,&ed.x,&ed.y,&d);        switch (d)        {            case 'N': st.dir = 0;break;            case 'E': st.dir = 1;break;            case 'S': st.dir = 2;break;            case 'W': st.dir = 3;break;        }        init();        s[st.x][st.y][st.dir].dis = 0;        s[st.x][st.y][st.dir].times = 1%m;        bfs();        int min = 0;        long long sum = 0;        for (int i=0;i<4;i++)        {            if (s[ed.x][ed.y][i].dis<s[ed.x][ed.y][min].dis)            {                min = i;                sum = s[ed.x][ed.y][i].times;            }            else            {                if (s[ed.x][ed.y][i].dis==s[ed.x][ed.y][min].dis)                {                    sum += s[ed.x][ed.y][i].times;                    sum %= m;                }            }        }        if (s[ed.x][ed.y][min].dis!=MAX_INT)            printf("%lld\n",sum);        else            printf("%d\n",-1);    }    return 0;}