迷宫的最短路径 -- BFS

来源：互联网发布：怎样学好plc编程编辑：程序博客网时间：2024/06/04 18:46
#include <iostream>#include <cstdio>#include <cstring>#include <cstdlib>#include <cmath>#include <vector>#include <queue>#include <algorithm>#include <set>#include <stack>using namespace std;#define MM(a) memset(a,0,sizeof(a))typedef long long LL;typedef unsigned long long ULL;const int maxn = 2*1e3+5;const int INF = 1e9+5;const int mod = 1000000007;const double eps = 1e-7;char map[105][105];int dis[105][105];int dx[4] = {1, -1, 0, 0};int dy[4] = {0, 0, -1, 1};int n, m;int sx, sy, ex, ey;typedef pair <int, int> P;void Init(){    for(int i=0; i<n; i++)    {        for(int j=0; j<m; j++)        {            dis[i][j] = INF;        }    }}int BFS(){    queue<P> que;    Init();    que.push(P(sx,sy));    dis[sx][sy] = 0;    while(que.size())    {        P p = que.front();        que.pop();        if(p.first==ex && p.second==ey)            break;        for(int i=0; i<4; i++)        {            int nx = p.first+dx[i];            int ny = p.second+dy[i];            if(nx>=0 && nx<n && ny>0 && ny<m && map[nx][ny]!='#' &&               dis[nx][ny]==INF)            {                que.push(P(nx, ny));                dis[nx][ny] = dis[p.first][p.second]+1;            }        }    }    return dis[ex][ey];}int main(){    while(cin>>n>>m)    {        for(int i=0; i<n; i++)            cin>>map[i];        for(int i=0; i<n; i++)        {            for(int j=0; j<m; j++)            {                if(map[i][j] == 'S')                {                    sx = i;                    sy = j;                }                if(map[i][j] == 'E')                {                    ex = i;                    ey = j;                }            }        }        printf("%d\n",BFS());    }    return 0;}/**#S######.#......#..#.#.##.##.#.#........##.##.####....#....#.#######.#....#......####.###.....#...E#**/
0 0