迷宫最短路径（三维和二维）

bfs

二维

AcWing

1101. 献给阿尔吉侬的花束

#include<bits/stdc++.h>

#define x first
#define y second

using namespace std;

typedef pair<int, int> PII;
const int N = 210 ;

int n, m;
char g[N][N];
int dist[N][N];

int bfs(PII start, PII end)
{
    queue<PII> q;
    memset(dist, -1, sizeof dist);
    
    dist[start.x][start.y] = 0;
    q.push(start);
    
    int dx[4] = {-1, 0, 1, 0}, dy[4] = {0, 1, 0, -1};
    while(q.size())
    {
        auto t = q.front();
        q.pop();
        
        for(int i = 0; i < 4; i ++)
        {
            int x = t.x + dx[i], y = t.y + dy[i];
            if(x < 0 || x >= n || y < 0 || y >= m) continue;
            if(g[x][y] == '#') continue;
            if(dist[x][y] != -1) continue;

            //  加上自身
            dist[x][y] = dist[t.x][t.y] + 1;  // 收集子节点的信息
        
            if(end == make_pair(x, y)) return dist[x][y];
            
            q.push({x, y});
            
        }
    }
    
    return -1; 
}

int main()
{
    int T; cin >> T;
    while(T --)
    {
        scanf("%d%d", &n, &m);
        for(int i = 0; i < n; i ++) scanf("%s", g[i]);
        
        PII start, end;
        for(int i = 0; i < n; i ++)
            for(int j = 0; j < m; j ++)
                if(g[i][j] == 'S') start = {i, j};
                else if(g[i][j] == 'E') end = {i, j};
    
        int distance = bfs(start, end);
        if(distance == -1) puts("oop!");
        else printf("%d\n", distance);
    }
    
    return 0;
}

---

三维度

#include<bits/stdc++.h>
using namespace std;
const int N = 110;
struct Point
{
  int x, y, z;
};

int L, R, C;
char g[N][N][N];
Point q[N * N * N];
int dist[N][N][N];

int dx[] = {1, -1, 0, 0, 0, 0};
int dy[] = {0, 0, 1, -1, 0, 0};
int dz[] = {0, 0, 0, 0, 1, -1};

int bfs(Point start, Point end)
{
    int hh = 0, tt = 0;
    q[0] =start;
    memset(dist, -1, sizeof dist);
    dist[start.x][start.y][start.z] = 0;
    
    while(hh <= tt)
    {
        auto t = q[hh ++];
        
        for(int i = 0; i < 6; i ++)
        {
            int x = t.x + dx[i], y = t.y + dy[i], z = t.z + dz[i];
            if(x < 0 || x >= L || y < 0 || y >= R || z < 0 || z >= C) continue;
            if(g[x][y][z] =='#') continue;
            if(dist[x][y][z] != -1) continue ;
            
            dist[x][y][z] = dist[t.x][t.y][t.z] + 1;
            if(x == end.x && y == end.y && z == end.z) return dist[x][y][z];
        
            q[++ tt] = {x, y, z};
        }
    }
    return -1 ;
}

int main()
{
    while(scanf("%d%d%d", &L, &R, &C), L || R || C)
    {
        Point start, end;
        for(int i = 0; i < L; i ++)
            for(int j = 0; j < R; j ++)
            {
                scanf("%s", g[i][j]);
                for(int k = 0; k < C; k ++)
                {
                    char c = g[i][j][k];
                    if(c == 'S') start = {i, j, k};
                    else if(c == 'E') end = {i, j, k};
                }
            }
        int distance = bfs(start, end);
        if(distance == -1) puts("Trapped!");
        else printf("Escaped in %d minute(s).\n", distance);
    }
    
    return 0;
}