Aizu 2325 Mysterious Maze

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不同的是题目给了你转向的方向序列

dis[x][y]表示到(x,y) 使用了最少的转向次数

#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include <queue>

using namespace std;

const int maxn = 1010;
const int inf = (1<<30);

int dx[4] = {-1,0,1,0};
int dy[4] = {0,1,0,-1};

struct node
{
    int x, y;
    node(int i = 0, int j = 0)
    {
        x = i, y = j;
    }
};

char s[1000010];
int g[maxn][maxn], dis[maxn][maxn], cost[1000010][4], dir[1000010];

int W,H,N;
queue<node>Q;

void init()
{
    memset(dis, -1, sizeof(dis));
    memset(g, 0, sizeof(g));

    dir[0] = 0;
    for(int i = 1; i <= N; ++ i)
        if(s[i] == 'L') dir[i] = (dir[i-1]+3)%4;
        else dir[i] = (dir[i-1]+1)%4;

    for(int i = N; i >= 0; -- i)
        for(int j = 0; j < 4; ++ j)
        {
            if(dir[i] == j) cost[i][j] = 0;
            else
            {
                if(i == N) cost[i][j] = inf;
                else cost[i][j] = cost[i+1][j] +1;
            }
        }
    for(int i = 0; i < 4; ++ i) cost[N+1][i] = inf;

    while(!Q.empty()) Q.pop();
}

bool solve(int sx, int sy, int ex, int ey)
{
    Q.push(node(sx, sy));
    dis[sx][sy] = 0;
    while(!Q.empty())
    {
        node u = Q.front();
        Q.pop();
        int now = dis[u.x][u.y];
        for(int i = 0; i < 4; ++ i)
        {
            int nx = u.x+dx[i], ny = u.y+dy[i];
            if(g[nx][ny] && cost[now][i] < inf)
            {
                if(nx == ex && ny == ey) return true;
                int tem = now+cost[now][i];
                if(dis[nx][ny] == -1 || tem < dis[nx][ny])
                {
                    dis[nx][ny] = tem;
                    Q.push(node(nx, ny));
                }
            }
        }
    }
    return false;
}

void show()
{
    for(int i = 0; i <= W+1; ++ i)
    {
        for(int j = 0; j <= H+1; ++ j)
            printf("%d ", g[i][j]);
        puts("");
    }
}

int main()
{
    while(scanf("%d%d%d", &W, &H, &N) ==3 && W+H+N)
    {
        scanf("%s", s+1);
        init();
        int sx, sy, ex, ey;
        for(int i = 1; i <= W; ++ i)
        {
            scanf("%s", s+1);
            for(int j = 1; j <= H; ++ j)
            {
                if(s[j] != '#') g[i][j] = 1;
                if(s[j] == 'S') sx = i, sy = j;
                if(s[j] == 'G') ex = i, ey = j;
            }
        }
       // show();
        if(solve(sx, sy, ex, ey)) puts("Yes");
        else puts("No");
    }
    return 0;
}