ZOJ 4020 Traffic Light（走迷宫变形）

传送门

我感觉就是一个走迷宫的题，只不过这个的墙是变化的。但是因为一直在0-1之间转换，所以把走到当前位置的步数进行判断，如果是奇数就把当前位置的灯状态改变，偶数不用处理，然后就是基本的搜索了。

#include<bits/stdc++.h>
using namespace std;
const int maxn = 1e5+10;
vector<int>mp[maxn];
vector<int>vis[maxn];
vector<int>step[maxn];
int n,m,si,sj,ei,ej;
typedef pair<int,int> pq;
int Bfs()
{
    queue <pq> que;
    while(!que.empty())
        que.pop();
    pq tmp;
    tmp.first = si;
    tmp.second = sj;
    que.push(tmp);
    step[si][sj] = 0;
    vis[si][sj] = 0;
    while(!que.empty())
    {
        pq top = que.front();
        que.pop();
        if(top.first == ei && top.second == ej)
            return step[top.first][top.second];
        int next_x,next_y;
        int pp = step[top.first][top.second];
        if(pp & 1)
            mp[top.first][top.second] = !mp[top.first][top.second];
        if(mp[top.first][top.second] == 0)
        {
            for(int i = 1;i <= 2; i++)
            {
                if(i == 1)
                {
                    next_x = top.first + 1;
                    next_y = top.second;
                }
                else if(i == 2)
                {
                    next_x = top.first - 1;
                    next_y = top.second;
                }
                if(next_x >= 1 && next_x <= n && next_y >= 1 && next_y <= m && !vis[next_x][next_y])
                {
                    pq dui;
                    dui.first = next_x;
                    dui.second = next_y;
                    que.push(dui);
                    vis[next_x][next_y] = 1;
                    step[next_x][next_y] = pp + 1;
                }
            }
        }
        else if(mp[top.first][top.second] == 1)
        {
            for(int i = 1;i <= 2; i++)
            {
                if(i == 1)
                {
                    next_x = top.first;
                    next_y = top.second + 1;
                }
                else if(i == 2)
                {
                    next_x = top.first;
                    next_y = top.second - 1;
                }
                if(next_x >= 1 && next_x <= n && next_y >= 1 && next_y <= m && !vis[next_x][next_y])
                {
                    pq dui;
                    dui.first = next_x;
                    dui.second = next_y;
                    que.push(dui);
                    vis[next_x][next_y] = 1;
                    step[next_x][next_y] = pp + 1;
                }
            }
        }
    }
    return -1;
}
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d %d",&n,&m);
        for(int i = 1;i <= n; i++)
        {
            mp[i].clear();
            vis[i].clear();
            step[i].clear();
            mp[i].resize(m+5);
            vis[i].resize(m+5);
            step[i].resize(m+5);
            for(int j = 1;j <= m; j++)
                scanf("%d",&mp[i][j]);
        }
        scanf("%d %d %d %d",&si,&sj,&ei,&ej);
        printf("%d\n",Bfs());
    }
    return 0;
}