萌新求助，不会bfs，dfs只有10分

PleasantSheep @ 2024-02-27 19:43:44

using namespace std;
int maze[105][105]={0};
int n, m;
int ans = 0;
int dx[4] = {-1, 1, 0, 0}, dy[4] = {0, 0, -1, 1};
void dfs(int x,int y)
{
    if(x==n&&y==m)
    {
        ans++;
    }
    for (int i = 0; i < 4;i++)
    {
        if(maze[x+dx[i]][y+dy[i]]==1)
        {
            maze[x + dx[i]][y + dy[i]] = 0;
            dfs(x + dx[i], y + dy[i]);
            maze[x + dx[i]][y + dy[i]] = 1;
        }
    }
}
int main()
{
    cin >> n >> m;
    char z;
    for (int i = 1; i <= n;i++)
    {
        for (int j = 1; j <= m;j++)
        {
            cin >> z;
            if(z=='.')
                maze[i][j] = 1;
            else
                maze[i][j] = 0;
        }
    }
    dfs(1, 1);
    if(ans>=1)
        cout << "Yes";
    else
        cout << "No";
    return 0;
}

by yuanshiren_qidong @ 2024-02-27 19:52:29

em......

by zcxxcz2110 @ 2024-02-27 20:03:15

刚才现场写的

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

int n, m;
int vis[110][110], walk[4][2] = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
char mp[110][110];
struct node
{
    int x, y;
};
queue<node> q;
void bfs(int x, int y)
{
    memset(vis, -1, sizeof vis);
    q.push({x, y});
    vis[x][y] = 0;
    while(!q.empty())
    {
        int xx = q.front().x, yy = q.front().y;
        q.pop();
        for(int i = 0; i < 4; i++)
        {
            int u = xx + walk[i][0], v = yy + walk[i][1];
            if(1 <= u && u <= n && 1 <= v && v <= m && vis[u][v] == -1 && mp[u][v] == '.')
            {
                q.push({u, v});
                vis[u][v] = vis[xx][yy] + 1;
            }
        }
    }
}

int main()
{
    cin >> n >> m;
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= m; j++) cin >> mp[i][j];
    bfs(1, 1);
    if(vis[n][m] != -1) cout << "Yes" << endl;
    else cout << "No" << endl;
    return 0;
}

by JOKER_chu @ 2024-02-27 20:05:28

@PleasantSheep

改出来了，你这问题太多了，看看我改的

100分

#include <bits/stdc++.h>
using namespace std;
int maze[105][105]={0};
int n, m;
int ans = 0;
int dx[4] = {-1, 1, 0, 0}, dy[4] = {0, 0, -1, 1};
void dfs(int x,int y)
{
    if(x==n&&y==m)
    {
        ans++;
        return ;
    }
    for (int i = 0; i < 4;i++)
    {
        if(x+dx[i] > 0 && x+dx[i] <= n && y+dy[i] > 0 && y+dy[i] <= m && maze[x+dx[i]][y+dy[i]]==0)
        {
            maze[x + dx[i]][y + dy[i]] = 1;
            dfs(x + dx[i], y + dy[i]);
        }
    }
}
int main()
{
    cin >> n >> m;
    char z;
    for (int i = 1; i <= n;i++)
    {
        for (int j = 1; j <= m;j++)
        {
            cin >> z;
            if(z=='.')
                maze[i][j] = 0;
            else
                maze[i][j] = 1;
        }
    }
    dfs(1, 1);
    if(ans>=1)
        cout << "Yes";
    else
        cout << "No";
    return 0;
}

by zcxxcz2110 @ 2024-02-27 20:10:32

#include <iostream>
#include <queue>
#include <cstring>
using namespace std;
int maze[105][105]={0}, vis[105][105] = {0};
int n, m;
int ans = 0;
int dx[4] = {-1, 1, 0, 0}, dy[4] = {0, 0, -1, 1};
void dfs(int x,int y)
{
    if(x==n&&y==m)
    {
        ans++;
    }
    for (int i = 0; i < 4;i++)
    {
        if(1 <= x + dx[i] && x + dx[i] <= n && 1 <= y + dy[i] && y + dy[i] <= m && vis[x + dx[i]][y + dy[i]] == -1 && maze[x+dx[i]][y+dy[i]]==1)
        {
            vis[x + dx[i]][y + dy[i]] = vis[x][y] + 1;
            maze[x + dx[i]][y + dy[i]] = 0;
            dfs(x + dx[i], y + dy[i]);
            maze[x + dx[i]][y + dy[i]] = 1;
        }
    }
}
int main()
{
    cin >> n >> m;
    char z;
    for (int i = 1; i <= n;i++)
    {
        for (int j = 1; j <= m;j++)
        {
            cin >> z;
            if(z=='.')
                maze[i][j] = 1;
            else
                maze[i][j] = 0;
        }
    }
    memset(vis, -1, sizeof vis);
    dfs(1, 1);
    if(ans>=1)
        cout << "Yes";
    else
        cout << "No";
    return 0;
}

by PleasantSheep @ 2024-02-28 20:07:21

@chuxm 感谢大佬指点！！！

by PleasantSheep @ 2024-02-28 20:08:54

@zcxxcz2110 感谢大佬！