HDU 5094 Maze （状压）

加一个维度，钥匙的状态，状压一下。n很小，钥匙也只有10个，bfs就好了。

忘了数组初始化。以后坚决不犯这种低级错误。

#include<cstdio>
#include<queue>
#include<cstring>
using namespace std;
const int maxn = 50+1;
int g[maxn][maxn][4];
int k[maxn][maxn];
int dx[] = {1,-1,0,0};
int dy[] = {0,0,1,-1};
int dir[5] = { 3,1,-1,0,2 };

struct node
{
    int x,y,step;
    int s;
    node(int X = 0, int Y = 0,int S = 0,int Step = 0) {
        x = X; y =Y; s = S; step = Step;
    }
};
int n,m,p;
bool vis[maxn][maxn][1024+10];
queue<node> q;
int tx,ty;

int bfs()
{
    memset(vis,0,sizeof(vis));
    while(q.size()) q.pop();
    node u(1,1,k[1][1],0);
    q.push(u);
    while(q.size()){
        u = q.front();q.pop();
        if(u.x == tx && u.y == ty) {return u.step;}
        for(int i = 0; i < 4; i++){
            if( g[u.x][u.y][i] == -1 || u.s&(1<<g[u.x][u.y][i])){
                int nx = u.x+dx[i], ny = u.y+dy[i], ns = u.s|k[nx][ny];
                if(1<=nx&&nx<=n&&1<=ny&&ny<=m&&!vis[nx][ny][ns>>1]){
                    vis[nx][ny][ns>>1] = 1;
                    q.push(node(nx,ny,ns,u.step+1));//+(g[u.x][u.y][i]!=-1)
                }
            }
        }
    }
    return -1;
}


int main()
{
    //freopen("E_in.txt","r",stdin);
    //freopen("E_out.txt","w",stdout);
    while(scanf("%d%d%d",&n,&m,&p) == 3){
        int K;
        scanf("%d",&K);
        memset(g,-1,sizeof(g));
        for(int i = 0; i < K; i++){
            int x1,x2,y1,y2,tp;
            scanf("%d%d%d%d%d",&x1,&y1,&x2,&y2,&tp);
            int Dir = dir[((y2-y1+1)<<1)+x2-x1];
            g[x1][y1][Dir] = tp;
            g[x2][y2][Dir^1] = tp;
        }
        int S;
        memset(k,0,sizeof(k));
        scanf("%d",&S);
        for(int i = 0; i < S; i++){
            int x0,y0,tp;
            scanf("%d%d%d",&x0,&y0,&tp);
            if(tp)
            k[x0][y0] |= 1<<tp;
        }
        tx = n; ty = m;
        int ans = bfs();
        printf("%d
",ans);
    }
    return 0;
}