hdu 4634 Swipe Bo bfs+状态压缩

题目链接

状态压缩记录当前拿到了哪些钥匙， 然后暴力搜索。

搞了好几个小时， 一开始也不知道哪里错了， 最后A了也不知道一开始哪里有问题。

#include <iostream>
#include <vector>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <map>
#include <set>
#include <string>
#include <queue>
#include <stack>
#include <bitset>
using namespace std;
#define pb(x) push_back(x)
#define ll long long
#define mk(x, y) make_pair(x, y)
#define lson l, m, rt<<1
#define mem(a) memset(a, 0, sizeof(a))
#define rson m+1, r, rt<<1|1
#define mem1(a) memset(a, -1, sizeof(a))
#define mem2(a) memset(a, 0x3f, sizeof(a))
#define rep(i, n, a) for(int i = a; i<n; i++)
#define fi first
#define se second
typedef pair<int, int> pll;
const double PI = acos(-1.0);
const double eps = 1e-8;
const int mod = 1e9+7;
const int inf = 1061109567;
const int dir[][2] = { {-1, 0}, {1, 0}, {0, -1}, {0, 1} };
const int maxn = 201;
int n, m, cnt, g[maxn][maxn];
bool vis[maxn][maxn][1<<7][4], used[maxn][maxn][1<<7];
char s[maxn][maxn];
struct node
{
    int x, y, step, key;
    node(){}
    node(int _x, int _y, int _step, int _key): x(_x), y(_y), step(_step), key(_key){}
};
queue <node> q;
int check(int x, int y) {
    if(x>=0&&x<n&&y>=0&&y<m)
        return 1;
    return 0;
}
int judge(int x, int y) {
    if(x == 1)
        return 0;
    if(x == -1)
        return 1;
    if(y == 1)
        return 2;
    if(y == -1)
        return 3;
}
void bfs(int x, int y) {
    mem(vis);
    mem(used);
    while(!q.empty())
        q.pop();
    used[x][y][0] = 1;
    q.push(node(x, y, 0, 0));
    while(!q.empty()) {
        node temp = q.front(); q.pop();
        int x = temp.x, y = temp.y, tmpx, tmpy;
        for(int i = 0; i < 4; i++) {
            int dirx = dir[i][0], diry = dir[i][1];
            tmpx = x, tmpy = y;
            int key = temp.key;
            node tmp = temp;
            if(!check(tmpx+dirx, tmpy+diry) || s[tmpx+dirx][tmpy+diry]=='#')
                continue;
            while(1) {
                if(s[tmpx][tmpy] == 'L')
                    dirx = 0, diry = -1;
                if(s[tmpx][tmpy] == 'R')
                    dirx = 0, diry = 1;
                if(s[tmpx][tmpy] == 'U')
                    dirx = -1, diry = 0;
                if(s[tmpx][tmpy] == 'D')
                    dirx = 1, diry = 0;
                int tmpdir = judge(dirx, diry);
                if(vis[tmpx][tmpy][tmp.key][tmpdir])
                    break;
                vis[tmpx][tmpy][tmp.key][tmpdir] = 1;
                if(s[tmpx][tmpy] == 'E' && key == (1<<cnt)-1) {
                    printf("%d
", temp.step+1);
                    return ;
                }
                if(s[tmpx][tmpy] == 'K')
                    key |= g[tmpx][tmpy];
                if(check(tmpx+dirx, tmpy+diry)) {
                    if(s[tmpx+dirx][tmpy+diry] == '#') {
                        tmp.x = tmpx;
                        tmp.y = tmpy;
                        tmp.step++;
                        tmp.key = key;
                        q.push(tmp);
                        used[tmpx][tmpy][tmp.key] = 1;
                        break;
                    } else {
                        tmpx += dirx;
                        tmpy += diry;
                    }
                } else {
                    break;
                }
            }
        }
    }
    puts("-1");
    return ;
}
void solve() {
    cnt = 0;
    int x, y;
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            if(s[i][j] == 'S')
                x = i, y = j;
            if(s[i][j] == 'K') {
                g[i][j] = 1<<cnt;
                cnt++;
            }
        }
    }
    bfs(x, y);
}
void read() {
    for(int i = 0; i < n; i++)
        scanf("%s", s[i]);
}
int main()
{
    while(scanf("%d%d", &n, &m)!=EOF) {
        read();
        solve();
    }
    return 0;
}