acm-uva10653解题报告

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题目网址：https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=18&page=show_problem&problem=1594

题目大意：二维迷宫求最短路

解题思想：标准BFS

代码：

#include <cstdio>

#include <queue>
#include <cstring>
using namespace std;
#define MAXN 1100

int map[MAXN][MAXN],book[MAXN*MAXN];
const int dir[4][2] = {{-1,0},{0,-1},{0,1},{1,0}};

int main()
{
    int R,C;
    while(scanf("%d%d",&R,&C)&&R!=0&&C!=0)
    {
        int k;
        scanf("%d",&k);
        memset(map,0,sizeof map);
        for(int i=0;i<k;i++)
        {
            int r,n;
            scanf("%d%d",&r,&n);
            for (int j=0;j<n;j++)
            {
                int x;
                scanf("%d",&x);
                map[r][x]=1;
            }
        }
        int x,y;
        scanf("%d%d",&x,&y);
        int start=x*C+y;
        scanf("%d%d",&x,&y);
        int finish=x*C+y;
        queue<int>q;
        memset(book,-1,sizeof book);
        q.push(start);book[start]=0;
        while (!q.empty())
        {
            int u=q.front();
            q.pop();
            if (u==finish)break;
            int x=u/C;
            int y=u%C;
            for (int i=0;i<4;i++)
            {
                int dx=x+dir[i][0],dy=y+dir[i][1];
                int v=dx*C+dy;
                if (dx>=0&&dx<R&&dy>=0&&dy<C&&map[dx][dy]==0&&book[v]==-1)
                {
                    book[v]=book[u]+1;
                    q.push(v);
                }
            }
        }
        printf("%d\n", book[finish]);
    }
    return 0;
}

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