poj3083

dfs+bfs，由于bfs的时候忘了加vis判断是否已入队，而多次超内存。

#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <queue>
using namespace std;

#define maxn 45

struct XPoint
{
    int x, y, d;
    XPoint(int xx, int yy, int dd) :
        x(xx), y(yy), d(dd)
    {
    }
    XPoint()
    {
    }
} s, e;

int dir[4][2] = //r, u, l, d
        {
        { 0, 1 },
        { -1, 0 },
        { 0, -1 },
        { 1, 0 } };
bool map[maxn][maxn];
bool vis[maxn][maxn];
int n, m;
int ansl, ansr, ans;

bool ok(int x, int y)
{
    if (x >= n || x < 0 || y >= m || y < 0)
        return false;
    if (!map[x][y])
        return false;
    return true;
}

void input()
{
    scanf("%d%d", &m, &n);
    getchar();
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < m; j++)
        {
            char ch;
            scanf("%c", &ch);
            if (ch == '.')
                map[i][j] = true;
            else
                map[i][j] = false;
            if (ch == 'S')
            {
                s.x = i;
                s.y = j;
            }
            if (ch == 'E')
            {
                e.x = i;
                e.y = j;
                map[i][j] = true;
            }
        }
        getchar();
    }
    if (s.x == 0)
        s.d = 3;
    if (s.x == n - 1)
        s.d = 1;
    if (s.y == 0)
        s.d = 0;
    if (s.y == m - 1)
        s.d = 2;
}

void dfs(XPoint a, int step, int dc)
{
    if (a.x == e.x && a.y == e.y)
    {
        ans = step;
        return;
    }
    for (int i = -1; i < 3; i++)
    {
        int x, y, d;
        d = (a.d + i * dc + 4) % 4;
        x = a.x + dir[d][0];
        y = a.y + dir[d][1];
        if (ok(x, y))
        {
            dfs(XPoint(x, y, d), step + 1, dc);
            break;
        }
    }
}

void bfs()
{
    int x, y;
    memset(vis, 0, sizeof(vis));
    queue<XPoint> q;
    s.d = 1;
    q.push(s);
    while (!q.empty())
    {
        XPoint temp = q.front();
        q.pop();
        for (int i = 0; i < 4; i++)
        {
            x = temp.x + dir[i][0];
            y = temp.y + dir[i][1];
            if (e.x == x && e.y == y)
            {
                ans = temp.d + 1;
                return;
            }
            if (ok(x, y) && !vis[x][y])
            {
                q.push(XPoint(x, y, temp.d + 1));
                vis[x][y] = true;
            }
        }
    }
}

int main()
{
    //freopen("D:\\t.txt", "r", stdin);
    int t;
    scanf("%d", &t);
    while (t--)
    {
        input();
        dfs(s, 1, -1);
        ansl = ans;
        dfs(s, 1, 1);
        ansr = ans;
        bfs();
        printf("%d %d %d\n", ansl, ansr, ans);
    }
    return 0;
}